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                                                                    Exhibit 10.1

                      FIFTH AMENDMENT TO AND RESTATEMENT
                                    OF THE
                    BANCFIRST CORPORATION STOCK OPTION PLAN



1.   PURPOSE. This Fifth Amendment to and Restatement of the BancFirst
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     Corporation Stock Option Plan (the "Plan") incorporates amendments adopted
     by the Board of Directors on April 26, 2001, and intended to be effective
     at such date subject to the ratification of such amendments by the
     stockholders of BancFirst Corporation (together with its "Subsidiaries," as
     defined below, the "Corporation") at the next annual meeting of
     stockholders following such adoption by the Board of Directors. The Plan is
     intended as an incentive and to encourage stock ownership by certain key
     employees and officers of the Corporation in order to increase their
     proprietary interest in the Corporation's success.

2.   DEFINITIONS. As used herein, the following terms shall have the
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     corresponding meanings:

     2.1.  "Committee" shall mean the Board of Directors of the Corporation, or
           a duly constituted committee of the Board consisting of three or more
           members, at least a majority of which shall be "Non-Employee
           Directors" as such term is used in Rule 16b-3 promulgated under the
           Securities Exchange Act of 1934, as amended (the "Exchange Act").

     2.2   "Common Stock" shall mean the common stock, par value $1.00 per
           share, of the Corporation.

     2.3.  "Date of Grant" shall mean the date of grant of a Stock Option
           granted hereunder as set forth in the Stock Option Agreement. In the
           event of a grant conditioned, among other things, upon stockholder
           ratification of this Plan, the date of such conditional grant shall
           be the Date of Grant for purposes of this Plan.

     2.4.  "Employee" shall mean any common-law employee of the Corporation. The
           determination of whether or not a person is an Employee of the
           Corporation with respect to the grant or exercise of an Incentive
           Stock Option shall be made in accordance with the rule of Income Tax
           Regulation Section 1.421-7(h) (or successor regulation).

     2.5.  "Fair Market Value" shall mean, with respect to the exercise of an
           option under the Plan, (a) if the Common Stock is listed on a
           national securities exchange or
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           the NASDAQ National Market System, the closing price of the Common
           Stock for the business day immediately preceding the day for which
           the determination is being made, or (b) if the Common Stock is not
           then listed on an exchange, the average of the closing bid and asked
           prices per share for the Common Stock in the over-the-counter market
           as quoted on NASDAQ for the business day immediately preceding the
           day for which the determination is being made, or (c) if the Common
           Stock is not then listed on any exchange or quoted on NASDAQ, an
           amount determined in good faith by the Committee to be the fair
           market value of the Common Stock, after consideration of all relevant
           factors.

     2.6   "Nonqualified Stock Option" shall mean a Stock Option which is not
           intended to qualify for tax treatment as an "incentive stock option"
           under Section 422 of the Code.

     2.7.  "Option Exercise Price" shall mean the price paid for Shares upon the
           exercise of a Stock Option granted hereunder.

     2.8.  "Optionee" shall mean any person entitled to exercise a Stock Option
           pursuant to the terms of the Plan.

     2.9.  "Stock Option" shall mean a stock option giving an Optionee the right
           to purchase shares of the Corporation's Common Stock. Stock Options
           granted under the Plan shall be Nonqualified Stock Options.

3.   ADMINISTRATION.
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     3.1   AUTHORITY; INDEMNIFICATION. Within the limitations described herein,
           the Committee shall administer the Plan, select the Employees of the
           Corporation, including officers of the Corporation, to whom Stock
           Options shall be granted, determine the number of Shares to be
           subject to each grant, determine the method of payment upon exercise
           of each Stock Option, determine all other terms of Stock Options
           granted hereunder and interpret, construe and implement the
           provisions of the Plan. All questions of interpretation of the Plan
           or any Stock Option granted under the Plan shall be determined by the
           Committee, and such decisions shall be binding upon all persons
           having an interest in the Plan and/or any Stock Option. No member of
           the Committee shall be liable for any action or determination made in
           good faith, and the members shall be entitled to indemnification and
           reimbursement in the manner provided in the Corporation's Certificate
           of Incorporation, or as otherwise permitted by law.

     3.2   RULE 16B-3 COMPLIANCE. With respect to the participation of eligible
           participants who are subject to Section 16(b) of the Exchange Act,
           the Plan shall be administered in compliance with the requirements of
           Rule 16b-3.

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     3.3   SECTION 162(M) COMPLIANCE. In the event the Corporation is a
           "publicly held corporation" as defined in paragraph (2) of section
           162(m) of the Code, as amended by the Revenue Reconciliation Act of
           1993 (P.L. 103-66), and the regulations promulgated thereunder
           ("Section 162(m)"), the Corporation shall establish a committee of
           outside directors meeting the requirements of Section 162(m) to
           approve the grant of Stock Options which might reasonably be
           anticipated to result in the payment of employee remuneration that
           would otherwise exceed the limit on employee remuneration deductible
           for income tax purposes pursuant to Section 162(m).

4.   ELIGIBILITY.  The individuals who shall be eligible to participate in the
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     Plan shall be such key Employees (including officers) of BancFirst
     Corporation, or of any corporation ("Subsidiary") in which the Corporation
     has proprietary interest by reason of stock ownership or otherwise,
     including any corporation in which the Corporation acquires a proprietary
     interest after the adoption of this Plan (but only if the Corporation owns,
     directly or indirectly, stock possessing not less than 50% of the total
     combined voting power of all classes of stock in the corporation), as the
     Committee shall determine from time to time.

5.   STOCK. The stock subject to Stock Options and other provisions of the Plan
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     shall be shares of the Corporation's authorized but unissued Common Stock
     or treasury stock, as determined by the Committee. Subject to adjustment in
     accordance with the provisions of Subparagraph 6.7 hereof, the total number
     of shares of Common Stock of the Corporation on which Stock Options may be
     granted under the Plan shall not exceed in the aggregate 1,100,000 shares.
     In the event that any outstanding Stock Option under the Plan for any
     reason expires or is terminated prior to the end of the period during which
     Stock Options may be granted, the shares of the Common Stock allocable to
     the unexercised portion of such Stock Option may again be subject to a
     Stock Option under the Plan.

6.   TERMS AND CONDITIONS OF STOCK OPTIONS. Stock Options granted pursuant to
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     the Plan shall be evidenced by agreements in such form as the Committee
     shall, from time to time, approve. Agreements shall comply with and be
     subject to the following terms and conditions:

     6.1   MEDIUM AND TIME OF PAYMENT. The Option Exercise Price shall be
           payable in United States Dollars upon the exercise of the Stock
           Option and may be paid in cash or by certified check, bank draft or
           money order payable to the order of the Corporation, unless otherwise
           determined by the Committee.

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     6.2   NUMBER OF SHARES. The Stock Option shall state the total number of
           shares to which it pertains.

     6.3   OPTION EXERCISE PRICE. The Option Exercise Price shall be equal to
           the Fair Market Value of the Common Stock on the Date of Grant.

     6.4   TERM OF STOCK OPTIONS. Any Stock Option granted must be exercised
           within fifteen (15) years of the date of such grant. Additionally,
           any Stock Option with an eleven (11) year term previously granted
           under this Plan, prior to its amendment, may also be exercised within
           fifteen (15) years of the date of such prior issuance.

     6.5   DATE OF EXERCISE. Unless otherwise determined by the Committee at the
           time of granting a Stock Option, Stock Options shall be exercisable
           at the rate set forth below beginning four years from the Date of
           Grant. After becoming exercisable, the Stock Option may be exercised
           at any time and from time to time in whole or in part until
           termination of the Stock Option as set forth in Sections 6.4 or 6.6.

<TABLE>
<CAPTION>

           Cumulative
           Elapsed Years from              Percent     Percent
           Date of Grant                  of Shares   of Shares
           -------------                  ---------   ---------
<S>                                       <C>         <C>

           less than 4 years                   0%          0%
           4 to 5 years                       25%         25%
           5 to 6 years                       25%         50%
           6 to 7 years                       25%         75%
           more than 7 years                  25%        100%
</TABLE>

     6.6   TERMINATION OF EMPLOYMENT. In the event that an Optionee's employment
           by the Corporation shall terminate, his Stock Option whether or not
           then exercisable shall terminate immediately; provided, however, that
           if the termination is not as a result of embezzlement, theft or other
           violation of the law, the Optionee shall have the right to exercise
           his option (to the extent exercisable at the time of termination) at
           any time within 30 days after such termination; provided, further,
           that if any termination of employment is related to the Optionee's
           retirement with the consent of the Corporation, the Optionee shall
           have the right to exercise his Stock Option (to the extent
           exercisable up to the date of retirement) at any time within three
           months after such retirement; and provided, further, that if the
           Optionee shall die while in the employment of the Corporation or
           within the period of time after termination of employment or
           retirement during

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           which he was entitled to exercise his option as hereinabove provided,
           his estate, personal representative, or beneficiary shall have the
           right to exercise his Stock Option (to the extent exercisable at the
           date of death) at any time within twelve (12) months from the date of
           his death.

     6.7   RECAPITALIZATION. The aggregate number of shares of Common Stock on
           which Stock Options may be granted to persons participating under the
           Plan, the number of shares thereof covered by each outstanding Stock
           Option, and the price per share thereof in each such Stock Option,
           shall all be proportionately adjusted for any increase or decrease in
           the number of issued shares of Common Stock of the Corporation
           resulting from a subdivision or consolidation of shares or other
           capital adjustment, or the payment of a stock dividend or other
           increase or decrease in such shares, effected without receipt of
           consideration by the Corporation; provided, however, that any
           fractional shares resulting from such adjustment shall be eliminated.
           In the event of a change in the Corporation's Common Stock which is
           limited to a change in the designation thereof to "Capital Stock" or
           other similar designation, or a change in the par value thereof, or
           from par value to no par value, without increase in the number of
           issued shares, the shares resulting from any such change shall be
           deemed to be Common Stock within the meaning of the Plan.

     6.8   REORGANIZATION OF CORPORATION. Subject to any required action by the
           stockholders, if the Corporation shall be the surviving or resulting
           corporation in any merger or consolidation which does not result in
           change of control of the Corporation, any Stock Option granted
           hereunder shall pertain to and apply to the securities to which a
           holder of the number of shares of Common Stock subject to the Stock
           Option would have been entitled. In the event of a dissolution or
           liquidation of the Corporation or a merger or consolidation in which
           the Corporation is not the surviving or resulting corporation or
           which results in a change in control of the Corporation, or a tender
           or exchange offer which results in a change in control of the
           Corporation, the Committee shall determine: (i) whether all or any
           part of the unexercisable portion (as set forth in section 6.5) of
           any Stock Option outstanding under the Plan shall terminate; (ii)
           whether the Stock Options shall become immediately exercisable; or
           (iii) whether such Stock Options may be exchanged for options
           covering securities of any such surviving or resulting corporation,
           subject to the agreement of any such surviving or resulting
           corporation, on terms and conditions substantially similar to a Stock
           Option hereunder.

     6.9   ASSIGNABILITY. Except as provided in this Section, no Stock Option
           shall be assignable or transferable except as follows:

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           (a)  by will or by the laws of descent and distribution.
           (b)  for the purpose of making a charitable gift.

           (c)  to the Optionee as trustee of a revocable trust which allows the
                Optionee to amend or revoke the trust at any time. If the
                Optionee relinquishes his power to amend or revoke the trust or
                appoints a trustee other than the Optionee, the Optionee shall
                withdraw the Stock Option from the trust prior to the
                relinquishment of such power or appointment and revest title to
                the Stock Option in the Optionee's individual name. If the trust
                becomes irrevocable due to the death of the Optionee, the
                successor trustee shall have the same power to exercise the
                Stock Option under Section 6.6 as the personal representative.
                If there is a successor trustee under the trust due to the
                incapacity of the Optionee, the date of incapacity shall be
                treated as termination of employment under Section 6.6, and the
                successor trustee shall have the same right to exercise the
                option as the Optionee has under Section 6.6. The trustee or any
                successor trustee shall be bound by all the terms and conditions
                of the Plan and the Stock Option Agreement entered into by the
                Plan and Optionee under this Plan.

           (d)  to the extent set forth in the Stock Option Agreement governing
                such Stock Option.

     6.10  OPTIONEE'S AGREEMENT. If, at the time of the exercise of any Stock
           Option, it is necessary or desirable, in order to comply with any
           applicable laws or regulations relating to the sale of securities,
           that the Optionee exercising the Stock Option shall agree that he
           will purchase the shares that are subject to the Stock Option for
           investment and not with any present intention to resell the same, the
           Optionee will, upon the request of the Corporation, execute and
           deliver to the Corporation an agreement to such effect.

     6.11  RIGHTS AS A STOCKHOLDER. An Optionee shall have no rights as a
           stockholder with respect to shares covered by his Stock Option until
           the date of issuance of the shares to him and only after such shares
           are fully paid.

     6.12  OTHER PROVISIONS. The option agreements authorized under the Plan may
           contain such other provisions as the Committee shall deem advisable.

7.   MARKETABILITY OF SHARES. The Common Stock is currently traded on the NASDAQ
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     National Market System. As a result, its liquidity varies widely in
     response to


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     supply and demand. Consequently, the Corporation can give no assurances as
     to the marketability of shares acquired under the Plan.

8.   TAX IMPLICATIONS. It is anticipated that Stock Options granted under the
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     Plan will be treated as Nonqualified Stock Options by the Internal Revenue
     Service. As such, exercise of the Stock Option would generate a taxable
     event with the difference between the original Option Exercise Price and
     the Fair Market Value of the Common Stock at the time of exercise being
     treated as ordinary income.

9.   TERM OF PLAN. No Stock Option may be granted after December 31, 2011.
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10.  NO OBLIGATION TO EXERCISE OPTION. The granting of a Stock Option shall
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     impose no obligation upon the Optionee to exercise such Stock Option.

11.  AMENDMENTS. The Board of Directors may from time to time amend, alter,
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     suspend, or discontinue the Plan or alter or amend (including decrease of
     the Option Exercise Price by cancellation and substitution of options or
     otherwise) any and all option agreements granted thereunder; provided,
     however, that after the first registration of the Common Stock under
     Section 12 of the Securities Exchange Act of 1934, no such action of the
     Board of Directors may, without approval of the stockholders of the
     Corporation, alter the provisions of the Plan so as to (a) materially
     increase the benefits accruing to participants under the Plan; (b)
     materially increase the number of securities which may be issued under the
     Plan; or (c) materially modify the requirements as to eligibility for
     participation in the Plan; and provided, further, that no amendment may,
     without the consent of the Optionee, affect any then outstanding Stock
     Options or unexercised portions thereof. In addition, the approval of the
     Corporation's stockholders shall be sought for any amendment to the Plan or
     a Stock Option for which the Committee deems stockholder approval necessary
     in order to comply with Rule 16b-3.

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