----

**UNITED      STATES**

**SECURITIES      AND EXCHANGE COMMISSION**

**WASHINGTON,      D.C. 20549**

**FORM      10-Q**

| **x**                                                                                                                                                                                                                                                                                                    | **QUARTERLY                REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE                ACT OF                1934**  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                                                                                                                                                                     |
| For                the quarterly period ended March 31, 2006                                                                                                                                                                                                                                             |
|                                                                                                                                                                                                                                                                                                     |
|                                                                                                                                                                                                                                                                                                     | or                                                                                                                                        |
|                                                                                                                                                                                                                                                                                                     |                                                                                                                                      |
| o                                                                                                                                                                                                                                                                                                        | **TRANSITION                REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE                ACT OF                1934** |
|                                                                                                                                                                                                                                                                                                     |                                                                                                                                      |
| For                the transition period                from                                       to |

**KNIGHT      TRANSPORTATION, INC.**

| **Arizona**                                                                                 | **86-0649974**                                                    |
|---------------------------------------------------------------------------------------------|-------------------------------------------------------------------|
| (State                or other jurisdiction ofincorporation                or organization) | (I.R.S.                EmployerIdentification                No.) |

**5601      West Buckeye Road**

**Phoenix,      Arizona**

**85043**

**602-269-2000**

| Large                accelerated filer x | Accelerated                filer o | Non-accelerated                filer o |
|------------------------------------------|------------------------------------|----------------------------------------|

   oYes    x        No

----

**KNIGHT      TRANSPORTATION, INC.**

**INDEX**

| **PART                  I - FINANCIAL INFORMATION** | **Page                  Number**                                                                                                                |
|-----------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                |                                                                                                                                            |
| **Item                  1.**                        | **Financial                  Statements**                                                                                                       |   |
|                                                |                                                                                                                                            |   |
|                                                | Condensed                  Consolidated Balance Sheets as of March 31, 2006 and                  December 31, 2005 (Unaudited)                  | 3 |
|                                                |                                                                                                                                            |   |
|                                                | Condensed                  Consolidated Statements of Income for the three monthsended                  March 31, 2006 and 2005 (Unaudited)     | 5 |
|                                                |                                                                                                                                            |   |
|                                                | Condensed                  Consolidated Statements of Cash Flows for the threemonths                  ended March 31, 2006 and 2005 (Unaudited) | 6 |
|                                                |                                                                                                                                            |   |
|                                                | Notes                  to Condensed Consolidated Financial Statements (Unaudited)                                                               | 8 |
|                                                |                                                                                                                                            |   |
| **Item                  2.**                        | **Management's                  Discussion and Analysis of Financial Condition****and                  Results of Operation**                   | 14 |
|                                                |                                                                                                                                            |   |
| **Item                  3.**                        | **Quantitative                  and Qualitative Disclosures About Market Risk**                                                                 | 20 |
|                                                |                                                                                                                                            |   |
| **Item                  4.**                        | **Controls                  and Procedures**                                                                                                    | 21 |
|                                                |                                                                                                                                            |   |
| **PART                  II - OTHER INFORMATION**    |                                                                                                                                            |
|                                                |                                                                                                                                            |   |
| **Item                  1.**                        | **Legal                  Proceedings**                                                                                                          | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  1A.**                       | **Risk                  Factors**                                                                                                               | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  2.**                        | **Unregistered                  Sales of Equity Securities and Use of Proceeds**                                                                | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  3.**                        | **Defaults                  Upon Senior Securities**                                                                                            | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  4.**                        | **Submission                  of Matters to a Vote of Security Holders**                                                                        | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  5.**                        | **Other                  Information**                                                                                                          | 22 |
|                                                |                                                                                                                                            |   |
| **Item                  6.**                        | **Exhibits**                                                                                                                                    | 22 |
|                                                |                                                                                                                                            |   |
| **Signatures**                                      |                                                                                                                                            | 24 |

----

INDEX

| **PART                I - FINANCIAL INFORMATION**                        |
|-------------------------------------------------------------------------------|
| **Item                1.**  **Financial                Statements** |

| **KNIGHT                    TRANSPORTATION, INC. AND SUBSIDIARIES****Condensed                    Consolidated Balance Sheets (unaudited)****As                    of March 31, 2006 and December 31, 2005****(In                    thousands)** |   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                                                              |   |
|                                                                                                                                                                                                                                              |   | March                    31, 2006 |   | December                    31, 2005 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |
| ASSETS                                                                                                                                                                                                                                            |   |   |   |   |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |
| CURRENT                    ASSETS:                                                                                                                                                                                                                |   |   |   |   |   |
| Cash                    and cash equivalents                                                                                                                                                                                                      |   | $ | 27,816 |   | $ | 18,809 |   |
| Short-term                    investments                                                                                                                                                                                                         |   |   | 2,924 |   |   | 2,278 |   |
| Accounts                    receivable, net                                                                                                                                                                                                       |   |   | 68,925 |   |   | 79,848 |   |
| Notes                    receivable, net                                                                                                                                                                                                          |   |   | 248 |   |   | 241 |   |
| Inventories                    and supplies                                                                                                                                                                                                       |   |   | 3,544 |   |   | 3,355 |   |
| Prepaid                    expenses                                                                                                                                                                                                               |   |   | 8,607 |   |   | 7,156 |   |
| Restricted                    cash                                                                                                                                                                                                                |   |   | - |   |   | 211 |   |
| Deferred                    tax asset                                                                                                                                                                                                             |   |   | 8,491 |   |   | 8,533 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
| Total                    current assets                                                                                                                                                                                                           |   |   | 120,555 |   |   | 120,431 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
| PROPERTY                    AND EQUIPMENT:                                                                                                                                                                                                        |   |   |   |   |   |   |   |
| Land                    and improvements                                                                                                                                                                                                          |   |   | 18,163 |   |   | 18,163 |   |
| Buildings                    and improvements                                                                                                                                                                                                     |   |   | 34,749 |   |   | 34,482 |   |
| Furniture                    and fixtures                                                                                                                                                                                                         |   |   | 6,225 |   |   | 7,518 |   |
| Shop                    and service equipment                                                                                                                                                                                                     |   |   | 2,898 |   |   | 2,803 |   |
| Revenue                    equipment                                                                                                                                                                                                              |   |   | 448,451 |   |   | 430,048 |   |
| Leasehold                    improvements                                                                                                                                                                                                         |   |   | 378 |   |   | 378 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                              |   |   | 510,864 |   |   | 493,392 |   |
| Less:                    Accumulated depreciation       and                    amortization                                                                                                                         |   |   | (144,777 | ) |   | (141,053 | ) |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
| PROPERTY                    AND EQUIPMENT, net                                                                                                                                                                                                    |   |   | 366,087 |   |   | 352,339 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
| NOTES                    RECEIVABLE - long-term                                                                                                                                                                                                   |   |   | 372 |   |   | 344 |   |
| GOODWILL                                                                                                                                                                                                                                          |   |   | 8,439 |   |   | 8,119 |   |
| OTHER                    ASSETS                                                                                                                                                                                                                   |   |   | 3,451 |   |   | 2,594 |   |
|                                                                                                                                                                                                                                              |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                              |   | $ | 498,904 |   | $ | 483,827 |   |

----

INDEX

| **KNIGHT                  TRANSPORTATION, INC. AND SUBSIDIARIES****Condensed                  Consolidated Balance Sheets (unaudited) (continued)****As                  of March 31, 2006 and December 31, 2005****(In                  thousands, except par values)** |   |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |
|                                                                                                                                                                                                                                                                     |   | March                  31, 2006 |   | December                  31, 2005 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |
| LIABILITIES                  AND SHAREHOLDERS’ EQUITY                                                                                                                                                                                                              |   |   |   |   |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |
| CURRENT                  LIABILITIES:                                                                                                                                                                                                                                    |   |   |   |   |   |
| Accounts                  payable                                                                                                                                                                                                                                        |   | $ | 6,769 |   | $ | 7,464 |   |
| Accrued                  payroll                                                                                                                                                                                                                                         |   |   | 4,997 |   |   | 5,452 |   |
| Accrued                  liabilities                                                                                                                                                                                                                                     |   |   | 16,451 |   |   | 13,307 |   |
| Claims                  accrual                                                                                                                                                                                                                                          |   |   | 23,508 |   |   | 26,155 |   |
| Other                  current liabilities                                                                                                                                                                                                                               |   |   | - |   |   | 211 |   |
| Dividend                  payable                                                                                                                                                                                                                                        |   |   | - |   |   | 1,713 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| Total                  current liabilities                                                                                                                                                                                                                               |   |   | 51,725 |   |   | 54,302 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| DEFERRED                  INCOME TAXES                                                                                                                                                                                                                                   |   |   | 78,152 |   |   | 76,597 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| Total                  liabilities                                                                                                                                                                                                                                       |   |   | 129,877 |   |   | 130,899 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| COMMITMENTS                  AND CONTINGENCIES                                                                                                                                                                                                                           |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| SHAREHOLDERS’                  EQUITY:                                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Preferred                  stock, $0.01 par value;authorized                  50,000 shares;none                  issued and outstanding                                                                                                                                 |   |   | - |   |   | - |   |
| Common                  stock, $0.01 par value; authorized100,000                  shares; 85,813 and 85,666issued                  and outstanding at March 31, 2006and                  December 31, 2005, respectively                                                |   |   | 858 |   |   | 857 |   |
| Additional                  paid-in capital                                                                                                                                                                                                                              |   |   | 89,133 |   |   | 87,148 |   |
| Retained                  earnings                                                                                                                                                                                                                                       |   |   | 279,036 |   |   | 264,923 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
| Total                  shareholders’ equity                                                                                                                                                                                                                        |   |   | 369,027 |   |   | 352,928 |   |
|                                                                                                                                                                                                                                                                     |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                     |   | $ | 498,904 |   | $ | 483,827 |   |

----

INDEX

| **KNIGHT                TRANSPORTATION, INC. AND                SUBSIDIARIES****Condensed                Consolidated Statements of Income (unaudited)****(In                thousands, except per share data)** |   |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                             |   | Three                Months EndedMarch                31, |   |
|                                                                                                                                                                                                             |   |   |   |   |   |
|                                                                                                                                                                                                             |   | 2006 |   | 2005 |   |
| REVENUE:                                                                                                                                                                                                         |   |   |   |   |   |
| Revenue,                before fuel surcharge                                                                                                                                                                    |   | $ | 129,339 |   | $ | 111,074 |   |
| Fuel                surcharge                                                                                                                                                                                    |   |   | 19,713 |   |   | 11,107 |   |
| Total                revenue                                                                                                                                                                                     |   |   | 149,052 |   |   | 122,181 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| OPERATING                EXPENSES:                                                                                                                                                                               |   |   |   |   |   |   |   |
| Salaries,                wages and benefits                                                                                                                                                                      |   |   | 43,201 |   |   | 36,918 |   |
| Fuel                                                                                                                                                                                                             |   |   | 36,022 |   |   | 25,841 |   |
| Operations                and maintenance                                                                                                                                                                        |   |   | 9,427 |   |   | 7,632 |   |
| Insurance                and claims                                                                                                                                                                              |   |   | 5,754 |   |   | 6,365 |   |
| Operating                taxes and licenses                                                                                                                                                                      |   |   | 3,251 |   |   | 2,929 |   |
| Communications                                                                                                                                                                                                   |   |   | 1,310 |   |   | 976 |   |
| Depreciation                and amortization                                                                                                                                                                     |   |   | 14,600 |   |   | 12,309 |   |
| Lease                expense - revenue equipment                                                                                                                                                                 |   |   | 109 |   |   | - |   |
| Purchased                transportation                                                                                                                                                                          |   |   | 7,907 |   |   | 6,484 |   |
| Miscellaneous                operating expenses                                                                                                                                                                  |   |   | 1,373 |   |   | 1,580 |   |
|                                                                                                                                                                                                             |   |   | 122,954 |   |   | 101,034 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Income                from operations                                                                                                                                                                            |   |   | 26,098 |   |   | 21,147 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Interest                and investment income                                                                                                                                                                    |   |   | 284 |   |   | 110 |   |
|                                                                                                                                                                                                             |   |   | 284 |   |   | 110 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Income                before income taxes                                                                                                                                                                        |   |   | 26,382 |   |   | 21,257 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| INCOME                TAXES                                                                                                                                                                                      |   |   | (10,550 | ) |   | (8,500 | ) |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Net                income                                                                                                                                                                                        |   | $ | 15,832 |   | $ | 12,757 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Earnings                per common share and common share equivalent:                                                                                                                                            |   |   |   |   |   |   |   |
| Basic                                                                                                                                                                                                            |   | $ | 0.18 |   | $ | 0.15 |   |
| Diluted                                                                                                                                                                                                          |   | $ | 0.18 |   | $ | 0.15 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |
| Weighted                average number of common shares and common share equivalents                outstanding:                                                                                                 |   |   |   |   |   |   |   |
| Basic                                                                                                                                                                                                            |   |   | 85,752 |   |   | 85,121 |   |
| Diluted                                                                                                                                                                                                          |   |   | 87,260 |   |   | 87,047 |   |

----

INDEX

| **KNIGHT                TRANSPORTATION, INC. AND                SUBSIDIARIES****Condensed                Consolidated Statements of Cash Flows (unaudited)****(In                thousands)** |   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                          |   |   |   |
|                                                                                                                                                                                          |   | Three                Months EndedMarch                31, |   |
|                                                                                                                                                                                          |   |   |   |
|                                                                                                                                                                                          |   | 2006 |   | 2005 |   |
| CASH                FLOWS FROM OPERATING ACTIVITIES:                                                                                                                                          |   |   |   |   |   |
|                                                                                                                                                                                          |   |   |   |   |   |
| Net                income                                                                                                                                                                     |   | $ | 15,832 |   | $ | 12,757 |   |
| Adjustments                to reconcile net income to net cash provided by operating                activities:                                                                               |   |   |   |   |   |   |   |
| Depreciation                and amortization                                                                                                                                                  |   |   | 14,600 |   |   | 12,309 |   |
| Gain                on sales of equipment                                                                                                                                                     |   |   | (1,849 | ) |   | (629 | ) |
| Non-cash                compensation expense for issuance of stock to certainmember                of board of directors                                                                      |   |   | 33 |   |   | 15 |   |
| Provision                for allowance for doubtful accounts                                                                                                                                  |   |   | (156 | ) |   | (97 | ) |
| Tax                benefit on stock option exercises                                                                                                                                          |   |   | - |   |   | 545 |   |
| Stock                option expense                                                                                                                                                           |   |   | 675 |   |   | - |   |
| Deferred                income taxes                                                                                                                                                          |   |   | 1,597 |   |   | (600 | ) |
| Changes                in assets and liabilities:                                                                                                                                             |   |   |   |   |   |   |   |
| Tax                benefits related to stock-based compensation                                                                                                                               |   |   | (430 | ) |   | - |   |
| (Increase)                in short-term investments                                                                                                                                           |   |   | (647 | ) |   | - |   |
| (Increase)                decrease in trade receivables                                                                                                                                       |   |   | 11,079 |   |   | (1,660 | ) |
| (Increase)                in inventories and supplies                                                                                                                                         |   |   | (189 | ) |   | (582 | ) |
| (Increase)                in prepaid expenses                                                                                                                                                 |   |   | (1,451 | ) |   | (4,709 | ) |
| Decrease                in income tax receivable                                                                                                                                              |   |   | - |   |   | 3,216 |   |
| (Increase)                in other assets                                                                                                                                                     |   |   | (52 | ) |   | (538 | ) |
| (Decrease)                in accounts payable                                                                                                                                                 |   |   | (23 | ) |   | (906 | ) |
| Increase                in accrued liabilities, claims accrual and other                                                                                                                      |   |   | 260 |   |   | 6,728 |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Net                cash provided by operating activities                                                                                                                                      |   |   | 39,279 |   |   | 25,849 |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| CASH                FLOW FROM INVESTING ACTIVITIES:                                                                                                                                           |   |   |   |   |   |   |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Purchase                of property and equipment                                                                                                                                             |   |   | (36,487 | ) |   | (15,977 | ) |
| Proceeds                from sales of equipment                                                                                                                                               |   |   | 9,319 |   |   | 2,711 |   |
| (Increase)                decrease in notes receivable                                                                                                                                        |   |   | (35 | ) |   | 43 |   |
| Acquisition                contingent payment                                                                                                                                                 |   |   | (320 | ) |   | - |   |
| Restricted                cash                                                                                                                                                                |   |   | 211 |   |   | - |   |
| TRP                investment contribution                                                                                                                                                    |   |   | (806 | ) |   | - |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Net                cash used in investing activities                                                                                                                                          |   |   | (28,118 | ) |   | (13,223 | ) |

----

INDEX

| **KNIGHT                TRANSPORTATION, INC. AND SUBSIDIARIES****Condensed                Consolidated Statements of Cash Flows (unaudited)                (continued)****(In                thousands)** |   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                      |   | Three                Months EndedMarch                31, |   |
|                                                                                                                                                                                                      |   |   |   |
|                                                                                                                                                                                                      |   | 2006 |   | 2005 |   |
|  CASH                FLOW FROM FINANCING ACTIVITIES:                                                                                                                                                 |   |   |   |   |   |
|                                                                                                                                                                                                      |   |   |   |   |   |
| Dividends                paid                                                                                                                                                                             |   |   | (3,432 | ) |   | - |   |
| Tax                benefits related to stock-based compensation                                                                                                                                           |   |   | 430 |   |   | - |   |
| Proceeds                from exercise of stock options                                                                                                                                                    |   |   | 848 |   |   | 709 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Net                cash (used in) provided by financing activities                                                                                                                                        |   |   | (2,154 | ) |   | 709 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| NET                INCREASE IN CASH AND CASH EQUIVALENTS                                                                                                                                                  |   |   | 9,007 |   |   | 13,335 |   |
| CASH                AND CASH EQUIVALENTS, Beginning of period                                                                                                                                             |   |   | 18,809 |   |   | 25,357 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| CASH                AND CASH EQUIVALENTS, end of period                                                                                                                                                   |   | $ | 27,816 |   | $ | 38,692 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| SUPPLEMENTAL                DISCLOSURES:                                                                                                                                                                  |   |   |   |   |   |   |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Noncash                investing and financing transactions:                                                                                                                                              |   |   |   |   |   |   |   |
| Equipment                acquired in accounts payable                                                                                                                                                     |   | $ | 1,232 |   | $ | 3,497 |   |
| Net                book value of equipment traded                                                                                                                                                         |   | $ | 473 |   |   | - |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Cash                Flow Information:                                                                                                                                                                     |   |   |   |   |   |   |   |
| Income                taxes paid                                                                                                                                                                          |   | $ | 5,429 |   | $ | 1,114 |   |

----

INDEX

**KNIGHT      TRANSPORTATION, INC. AND      SUBSIDIARIES**

**NOTES      TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Unaudited)**

**Note      1.**
**Financial      Information**

**Note      2.**
**Stock-Based      Compensation**

----

INDEX

|                                                                                                                                                                 |   | Three                  Months EndedMarch                  31, 2005 |   |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------------------------|--------|
|                                                                                                                                                                 |   |                                                               |   |
| Net                  income                                                                                                                                          |   | $                                                                  | 12,757 |   |
| Deduct                  total stock-based compensation expense determined                  under fair-value based method for all awards,                  net of tax |   |                                                               | (284   | ) |
| Net                  income, including the effect of stock-based compensation                  expense                                                               |   | $                                                                  | 12,473 |   |
|      Basic                earnings per share:                                                                                               |   |                                                               |   |   |
|                 As                  reported                                         |   | $                                                                  | 0.15   |   |
| Pro                  forma                                                                                                                                           |   | $                                                                  | 0.15   |   |
|      Diluted                earnings per share:                                                                                             |   |                                                               |   |   |
|                 As                  reported                                         |   | $                                                                  | 0.15   |   |
| Pro                  forma                                                                                                                                           |   | $                                                                  | 0.14   |   |

|                                                          |   | Three                Months EndedMarch                31, |                      |
|---------------------------------------------------------------|--------|-----------------------------------------------------------|---------------------------|
|                                                          |   |                                                      |                      |   |   |
|                                                          |   | 2006                                                      |                      | 2005 |   |
|                                                          |   |                                                      |                      |   |   |
| Dividend                yield (1)                             |   |                                                      | .37%                      |   |   | .30% |   |
|                                                          |   |                                                      |                      |   |   |   |   |
| Expected                volatility (2)                        |   |                                                      | 31.86%                    |   |   | 48.00% |   |
|                                                          |   |                                                      |                      |   |   |   |   |
| Risk-free                interest rate (3)                    |   |                                                      | 4.71%                     |   |   | 4.00% |   |
|                                                          |   |                                                      |                      |   |   |   |   |
| Expected                terms (4)                             |   |                                                      | 7.35                years |   |   | 6.00                years |   |
|                                                          |   |                                                      |                      |   |   |   |   |
| Weighted                average fair value of options granted |   | $                                                         | 8.80                      |   | $ | 7.30 |   |

| (1)    | The                dividend yield is based on our historical experience and future                expectation of dividend payouts.                                                                                            |
|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |                                                                                                                                                                                                                          |
| (2)    | We                analyzed the volatility of our stock using historical data from January                1,                2003 through the end of the most recent period to estimate the expected                volatility. |

----

INDEX

| (3)    | The                risk-free interest rate assumption is based on U.S. Treasury securities                at                a constant maturity with a maturity period that most closely resembles                the                expected term of the stock option award.                     |
|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |                                                                                                                                                                                                                                                                                              |
| (4)    | The                expected terms of employee stock options represents the weighted-average                period the stock options are expected to remain outstanding and has                been                determined based on an analysis of historical exercise                behavior. |

|                                     |   | **Option                Totals** |      | **Weighted                Average Exercise****Price                Per Share ($)** |   |
|------------------------------------------|--------|----------------------------------|-----------|------------------------------------------------------------------------------------|--------|
|                                     |   |                             |      |                                                                               |   |
| Outstanding                12/31/2005    |   |                             | 4,562,511 |                                                                               |   | 10.68                    |   |
|                                     |   |                             |      |                                                                               |   |   |   |
| Granted                                  |   |                             | 12,000    |                                                                               |   | 20.64                    |   |
|                                     |   |                             |      |                                                                               |   |   |   |
| Exercised                                |   |                             | (142,036  | )                                                                                  |   | 5.97                    |   |
|                                     |   |                             |      |                                                                               |   |   |   |
| Forfeited                                |   |                             | (131,704  | )                                                                                  |   | 4.98                    |   |
|                                     |   |                             |      |                                                                               |   |   |   |
| Outstanding                as of 3/31/06 |   |                             | 4,300,771 |                                                                               |   | 11.01                    |   |

|                                              |   | **Unvested****Option                Totals** |      | **Weighted                Average Exercise****Price                Per Share ($)** |   |
|---------------------------------------------------|--------|----------------------------------------------|-----------|------------------------------------------------------------------------------------|--------|
|                                              |   |                                         |      |                                                                               |   |
| Unvested                Outstanding 12/31/2005    |   |                                         | 2,747,286 |                                                                               |   | 11.58                    |   |
|                                              |   |                                         |      |                                                                               |   |   |   |
| Granted                                           |   |                                         | 12,000    |                                                                               |   | 20.64                    |   |
|                                              |   |                                         |      |                                                                               |   |   |   |
| Vested                                            |   |                                         | (31,072   | )                                                                                  |   | 11.00                    |   |
|                                              |   |                                         |      |                                                                               |   |   |   |
| Forfeited                                         |   |                                         | (43,955   | )                                                                                  |   | 10.95                    |   |
|                                              |   |                                         |      |                                                                               |   |   |   |
| Unvested                Outstanding as of 3/31/06 |   |                                         | 2,684,259 |                                                                               |   | 11.64                    |   |

----

INDEX

| **Range                of Exercise Prices****($)**                                                             |   | **Number****Outstanding**                           |   | **Weighted                Avg.****Contractual****Years****Remaining** |   | **Weighted                Avg.****Exercise                Price****Per                Share****($)**                                         |   | **Number****Exercisable**                                                           |   | **Weighted                Avg.****Exercise                Price****Per                Share for Exercisable ($)** |
|----------------------------------------------------------------------------------------------------------------|--------|-----------------------------------------------------|--------|-----------------------------------------------------------------------|--------|----------------------------------------------------------------------------------------------------------------------------------------------|--------|-------------------------------------------------------------------------------------|--------|-------------------------------------------------------------------------------------------------------------------|
|                                                                                                           |   |                                                |   |                                                                  |   |                                                                                                                                         |   |                                                                                |   |                                                                                                              |
| 2.50                - 10.00                                  |   | 1,295,459        |   | 4.81                                                                  |   |                    5.22                  |   | 768,635                           |   | 4.02                    |
|  10.01                - 15.00                           |   | 1,933,636        |   | 8.16                                                                  |   | 12.13                                                   |   | 75,376                            |   | 12.11                        |
| 15.01                - 25.00                                 |   | 1,071,676        |   | 9.36                                                                  |   | 16.01                                                   |   | 772,501                      |   | 15.69                   |
| Overall                Total                                                                                   |   | 4,300,771        |   | 7.45                                                                  |   | 11.01                                                   |   | 1,616,512                    |   | 9.98                    |

**Note      3.**
**Earnings      Per Share (in thousands, except per share data)**

|                                                                                                                          |   | Three                Months EndedMarch                31, |   |
|-------------------------------------------------------------------------------------------------------------------------------|--------|-----------------------------------------------------------|--------|
|                                                                                                                          |   |                                                      |   |   |   |
|                                                                                                                          |   | 2006                                                      |   | 2005 |   |
|                                                                                                                          |   |                                                      |   |   |   |
| Weighted                average common shares                outstanding -                basic                               |   |                                                      | 85,752 |   |   | 85,121 |   |
|                                                                                                                          |   |                                                      |   |   |   |   |   |
| Effect                of stock options                                                                                        |   |                                                      | 1,508  |   |   | 1,926 |   |
|                                                                                                                          |   |                                                      |   |   |   |   |   |
| Weighted                average common share and common share equivalents                outstanding -                diluted |   |                                                      | 87,260 |   |   | 87,047 |   |
|                                                                                                                          |   |                                                      |   |   |   |   |   |
| Net                income                                                                                                     |   | $                                                         | 15,832 |   | $ | 12,757 |   |
|                                                                                                                          |   |                                                      |   |   |   |   |   |
| Earnings                per common share and common share equivalent                                                          |   |                                                      |   |   |   |   |   |
| Basic                                                                                                                         |   | $                                                         | 0.18   |   | $ | 0.15 |   |
| Diluted                                                                                                                       |   | $                                                         | 0.18   |   | $ | 0.15 |   |

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INDEX

**Note      4.**
**Segment      Information**

**Note      5.**
**New      Accounting Pronouncements**

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INDEX

**Note      7.**
**Commitments      and Contingencies**

**Note      8.**
**Stock      Split**

**Note      9.**
**Dividend**

**Note      10.**
**Other      Assets**

**Note      11.**
**Acquisition**

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INDEX

**Item      2.**
**Management's      Discussion and Analysis of Financial Condition and Results of      Operation**

**Cautionary      Note Regarding Forward-Looking Statements**

*Except      for certain historical information contained herein, this report contains      forward-looking statements that involve risks, assumptions, and uncertainties      which are difficult to predict. All statements, other than statements of      historical fact, are statements that could be deemed forward-looking statements,      including without limitation: any projections of earnings, revenues, or other      financial items, any statement of plans, strategies, and objectives of      management for future operations; any statements concerning proposed new      services or developments; any statements regarding future economic conditions      or      performance; and any statements of belief and any statement of assumptions      underlying any of the foregoing. Words such as "believe," "may," "could,"      "expects," "hopes," "anticipates," and "likely," and variations of these words,      or similar expressions, are intended to identify such forward-looking      statements. Actual events or results could differ materially from those      discussed in forward-looking statements. Factors that could cause or contribute      to such differences include, but are not limited to those discussed in the      section entitled "*
*Item      1A. Risk Factors*
*,"      set forth below. We do not assume, and specifically disclaim, any obligation      to      update any forward-looking statement contained in this report.*

**Introduction**

***Business      Overview***

***Operating      and Growth Strategy***

***Revenue      and Expenses***

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INDEX

***Recent      Results of Operations and Quarter-End Financial      Condition***

| · | Revenue,                before fuel surcharge, increased 16.4%, to $129.3 million from $111.1                million; |
|--------|-----------------------------------------------------------------------------------------------------------------------|
|   |                                                                                                                  |
| · | Net                income increased 24.1%, to $15.8 million from $12.8 million;                and                    |
|   |                                                                                                                  |
| · | Net                income per diluted share increased 23.8% to $0.18 from                $0.15.                       |

**Results      of Operations**

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INDEX

|                                             |   | **Quarter                Ended****March                31,**(Total                revenue) |   | **Quarter                Ended****March                31,**(Revenue                beforefuel                surcharge and expenses net of                fuel surcharge) |   |
|--------------------------------------------------|--------|--------------------------------------------------------------------------------------------|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                             |   |                                                                                       |   |                                                                                                                                                                       |   |   |   |   |   |
|                                             |   | **2006**                                                                                   |   | **2005**                                                                                                                                                                   |   | **2006** |   | **2005** |   |
|                                             |   |                                                                                       |   |                                                                                                                                                                       |   |   |   |   |   |
| Revenue                                          |   |                                                                                       | 100.0  | %                                                                                                                                                                          |   | 100.0 | % |   | 100.0 | % |   | 100.0 | % |
|                                             |   |                                                                                       |   |                                                                                                                                                                       |   |   |   |   |   |   |   |   |   |
| Operating                expenses:               |   |                                                                                       |   |                                                                                                                                                                       |   |   |   |   |   |   |   |   |   |
| Salaries,                wages and benefits      |   |                                                                                       | 29.0   |                                                                                                                                                                       |   | 30.2 |   |   | 33.4 |   |   | 33.2 |   |
| Fuel                                             |   |                                                                                       | 24.2   |                                                                                                                                                                       |   | 21.1 |   |   | 12.6 |   |   | 13.3 |   |
| Operations                and maintenance        |   |                                                                                       | 6.3    |                                                                                                                                                                       |   | 6.3 |   |   | 7.3 |   |   | 6.9 |   |
| Insurance                and claims              |   |                                                                                       | 3.9    |                                                                                                                                                                       |   | 5.2 |   |   | 4.4 |   |   | 5.7 |   |
| Operating                taxes and licenses      |   |                                                                                       | 2.2    |                                                                                                                                                                       |   | 2.4 |   |   | 2.5 |   |   | 2.7 |   |
| Communications                                   |   |                                                                                       | 0.9    |                                                                                                                                                                       |   | 0.8 |   |   | 1.0 |   |   | 0.9 |   |
| Depreciation                and amortization     |   |                                                                                       | 9.8    |                                                                                                                                                                       |   | 10.1 |   |   | 11.3 |   |   | 11.1 |   |
| Lease                expense - revenue equipment |   |                                                                                       | 0.1    |                                                                                                                                                                       |   | - |   |   | 0.1 |   |   | - |   |
| Purchased                transportation          |   |                                                                                       | 5.3    |                                                                                                                                                                       |   | 5.3 |   |   | 6.1 |   |   | 5.8 |   |
| Miscellaneous                operating expenses  |   |                                                                                       | 0.8    |                                                                                                                                                                       |   | 1.3 |   |   | 1.1 |   |   | 1.4 |   |
| Total                operating expenses          |   |                                                                                       | 82.5   |                                                                                                                                                                       |   | 82.7 |   |   | 79.8 |   |   | 81.0 |   |
| Income                from operations            |   |                                                                                       | 17.5   |                                                                                                                                                                       |   | 17.3 |   |   | 20.2 |   |   | 19.0 |   |
| Net                interest & other income   |   |                                                                                       | 0.2    |                                                                                                                                                                       |   | 0.1 |   |   | 0.2 |   |   | 0.1 |   |
| Income                before income taxes        |   |                                                                                       | 17.7   |                                                                                                                                                                       |   | 17.4 |   |   | 20.4 |   |   | 19.1 |   |
| Income                taxes                      |   |                                                                                       | 7.1    |                                                                                                                                                                       |   | 7.0 |   |   | 8.2 |   |   | 7.6 |   |
| Net                income                        |   |                                                                                       | 10.6   | %                                                                                                                                                                          |   | 10.4 | % |   | 12.2 | % |   | 11.5 | % |
|                                             |   |                                                                                       |   |                                                                                                                                                                       |   |   |   |   |   |   |   |   |   |

**Comparison      of Three Months Ended March 31, 2006 to Three Months Ended March 31,      2005**

----

INDEX

----

INDEX

**Liquidity      and Capital Resources**

----

INDEX

**Off-Balance      Sheet Transactions**

**Critical      Accounting Policies and Estimates**

**Revenue      Recognition.**

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INDEX

**Depreciation.**

**Claims      Accrual**
***.***

**Accounting      for Income Taxes.**

**Item      3.**  **    Quantitative      and Qualitative Disclosures About Market Risk**

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INDEX

**Interest      Rate Risk **

**Commodity      Price Risk **

**Item      4.** **    Controls      and      Procedures**

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INDEX

**PART      II - OTHER INFORMATION**

**Item      1.**
**Legal      Proceedings**

**Item      1A. **
**Risk      Factors **

**Item      2.**  
**Unregistered      Sales of Equity Securities and **
**Use      **
**of      Proceeds**

**Item      3.** **Defaults      Upon Senior Securities**

**Item      4.**
**    Submission      of      Matters to a Vote of Security Holders **

**Item      5.**  
**Other      Information**

**Item      6.**
**    Exhibits**

| Exhibit                No. |    | Description                                                                                                                                                                                                                                             |
|----------------------------|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                       |    |                                                                                                                                                                                                                                                    |
| Exhibit                3   |    | Articles                of Incorporation and Bylaws                                                                                                                                                                                                     |
|                       |    |                                                                                                                                                                                                                                                    |
|                       | (3.1)   | Restated                Articles of Incorporation of the Company. (Incorporated by reference                to                Exhibit 3.1 to the Company’s Registration Statement on Form S-1. No                33-83534.)                       |
|                       |    |                                                                                                                                                                                                                                                    |
|                       | (3.1.1) | First                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.1 to the Company’s report on                Form 10-K for the period ended December 31, 2000.) |
|                       |    |                                                                                                                                                                                                                                                    |
|                       | (3.1.2) | Second                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.2 to the Company’s Registration                Statement on Form S-3 No. 333-72130.)               |
|                       |    |                                                                                                                                                                                                                                                    |
|                       | (3.1.3) | Third                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.3 to the Company’s Report on                Form 10-K for the period ended December 31, 2002.)      |
|                       |    |                                                                                                                                                                                                                                                    |
|                       | (3.2)   | Restated                Bylaws of the Company. (Incorporated by reference to Exhibit 3.2                to the                Company’s Registration Statement on Form S-3 No.                333-72130.)                                         |
|                       |    |                                                                                                                                                                                                                                                    |

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INDEX

|                      | (3.2.1) | First                Amendment to Restated Bylaws of the Company. (Incorporated by reference                to                Exhibit 3.2.1 to the Company’s Report on Form 10-K for the period ended                December 31, 2002.)                                  |
|---------------------------|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (3.2.2) | Second                Amendment to Restated Bylaws of the Company. (Incorporated by reference                to                Exhibit 3.2.1 to the Company's Report on Form 8-K dated March 2,                2005 and                filed on March 4, 2005.)                 |
|                      |    |                                                                                                                                                                                                                                                                            |
| Exhibit                4  |    | Instruments                defining the rights of security holders, including                indentures                                                                                                                                                                         |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (4.1)   | Articles                4, 10, and 11 of the Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1 to this Report on Form                10-Q.)                                                                           |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (4.2)   | Sections                2 and 5 of the Restated Bylaws of the Company. (Incorporated by reference                to Exhibit 3.2 to this Report on Form 10-Q.)                                                                                                                   |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (4.3)   | Knight                Transportation, Inc. 2003 Stock Option Plan. (Incorporated by reference                from Exhibit 1 to the Company's Proxy Statement filed April 4, 2003                on                Schedule 14A.)                                                |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (4.3.1) | First                Amendment to Knight Transportation, Inc. 2003 Stock Option Plan.                (Incorporated by reference to Exhibit 10.10.1 to the Company's Report                of                Form 10-Q for the period ended March 31, 2005.)                     |
|                      |    |                                                                                                                                                                                                                                                                            |
| Exhibit                31 |    | Section                302 Certifications                                                                                                                                                                                                                                       |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (31.1)  | Certification                pursuant to Item 601(b)(31) of Regulation S-K, as adopted pursuant                to                Section 302 of the Sarbanes-Oxley Act of 2002, by Kevin P. Knight,                the                Company’s Chief Executive Officer.  |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (31.2)  | Certification                pursuant to Item 601(b)(31) of Regulation S-K, as adopted pursuant                to                Section 302 of the Sarbanes-Oxley Act of 2002, by David A. Jackson,                the                Company’s Chief Financial Officer. |
|                      |    |                                                                                                                                                                                                                                                                            |
| Exhibit                32 |    | Section                906 Certifications                                                                                                                                                                                                                                       |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (32.1)  | Certification                pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section                906 of                the Sarbanes-Oxley Act of 2002, by Kevin P Knight, the Company’s Chief                Executive Officer.                             |
|                      |    |                                                                                                                                                                                                                                                                            |
|                      | (32.2)  | Certification                pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section                906 of                the Sarbanes-Oxley Act of 2002, by David A. Jackson, the Company’s Chief                Financial Officer.                           |

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INDEX

**SIGNATURES**

|                                                     |   | KNIGHT                TRANSPORTATION, INC.                                                                                                    |
|----------------------------------------------------------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------|
|                                                     |   |                                                                                                                                          |
|                                                     |   |                                                                                                                                          |
|                                                     |   |                                                                                                                                          |
|     Date:                May 9, 2006 | By:    | /s/                Kevin P. Knight                                                                                                            |
|                                                     |   | Kevin                P. KnightChief                Executive Officer, in his capacity as such and on behalf of the                registrant  |
|                                                     |   |                                                                                                                                          |
|                                                     |   |                                                                                                                                          |
|                                                     |   |                                                                                                                                          |
|                                                     |   |                                                                                                                                          |
|     Date:                May 9, 2006 | By:    | /s/                David A. Jackson                                                                                                           |
|                                                     |   | David                A. JacksonChief                Financial Officer, in his capacity as such and on behalf of the                registrant |

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INDEX