----

**UNITED      STATES**

**SECURITIES      AND EXCHANGE COMMISSION**

**Washington,      D.C. 20549**

**FORM      10-K**

**[X]      ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT      OF      1934**

**[        ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES AND      EXCHANGE ACT OF 1934**

|   | Delaware                                                                                    |   | 74-2440850                                                         |   |
|--------|---------------------------------------------------------------------------------------------|--------|--------------------------------------------------------------------|--------|
|   | (State                or other jurisdiction ofincorporation                or organization) |   | (I.R.S.                Employer Identification                No.) |   |

|   | o                Yes |   | x No |
|--------|----------------------|--------|-----------|

|   | o                Yes |   | x                No |
|--------|----------------------|--------|---------------------|

|   | x                Yes |   | o                No |
|--------|----------------------|--------|---------------------|

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

**DOCUMENTS        INCORPORATED BY REFERENCE**

**PART        I**

**Item        1. Business. **

**Item        1A. Risk Factors.**

**Item        1B. Unresolved Staff Comments.**

**Item        2. Properties.**

**Item        3. Legal Proceedings. **

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

**PART        II**

**Item        5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer        Purchases of Equity Securities.**

**Item        6. Selected Financial Data.**

**Item        7. Management’s Discussion and Analysis of Financial Condition and Results of        Operation.**

**Item        7A. Quantitative and Qualitative Disclosures About Market        Risk.**

**Item        8. Financial Statements and Supplementary Data.**

**Item        9. Changes in and Disagreements With Accountants on Accounting and Financial        Disclosure.**

**Item        9A. Controls and Procedures.**

**Item        9A(T). Controls and Procedures.**

**Item        9B. Other Information.**

**PART        III**

**Item        10. Directors, Executives Officers and Corporate        Governances.**

**Item        11. Executive Compensation.**

**Item        12. Security Ownership of Certain Beneficial Owners and Management and Related        Stockholder Matters.**

**Item        13. Certain Relationships and Related Transactions, and Director Independences.        **

**Item        14. Principal Accounting Fees and Services.**

**PART        IV**

**ADDITIONAL        DISCLOSURE ITEMS PURSUANT TO        GENERAL INSTRUCTION J**

**Item        1112(b) of Regulation AB. Significant Obligors Financial        Information.**

**Item        1114(b)(2) and 1115(b) of Regulation AB. Significant Enhancement Provider        Financial Information.**

**Item        1117 of Regulation AB. Legal Proceedings**

**Item        1119 of Regulation AB. Affiliations and Certain Relationships and Related        Transactions**

**Item        1122 of Regulation AB. Compliance with Applicable Servicing        Criteria.**

** **

**Item        1123 of Regulation AB. Servicer Compliance Statement**

**Item        15. Exhibits, Financial Statement Schedules.**

| (b)                See above |
|------------------------------|

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**SIGNATURES**

|                                | Lehman XS Trust 2006-15                                |
|-------------------------------------|-------------------------------------------------------------|
|                                | Aurora                Loan Services LLC, as Master Servicer |
|                                |                                                        |
|  March                29, 2007 | /s/                E. Todd Whittemore                       |
|                                | By: E.                Todd Whittemore                  |
|                                | Title: Executive                Vice President         |
|                                | Aurora                Loan Services LLC, as Master Servicer |

----

**EXHIBIT      INDEX**

| **Exhibit                      Number** | **Description**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|-----------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 4                                       | Trust                        Agreement dated as of September 1, 2006, among Structured                        Asset Securities                        Corporation, as Depositor, Aurora Loan Services LLC, as Master                        Servicer,                        and LaSalle Bank National Association, as Trustee (incorporated                        herein by                        reference from Exhibit 4.1 of the Current Report on Form                        8-K of the                        registrant, as filed with the Commission on October 12,                        2006). |
| 10                                      | Incorporated                    by reference as Exhibit (4).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| 31                                      | Sarbanes-Oxley                      Certification                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| 33                                      | Report                    on assessment of                    compliance with servicing criteria for asset-backed                    securities                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| (a)                                     |     Aurora                      Loan Services LLC, as Master Servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| (b)                                     |     LaSalle                      Bank National Association, as Trustee, paying agent and                      Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| (c)                                     |     Deutsche                      Bank                      National Trust Company, as Custodian and as subcontractor for                      IndyMac                      Bank, FSB                                                                                                                                                                                                                                                                                                                                                                                                    |
| (d)                                     |     US                      Bank                      National Association, as Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| (e)                                     |     Wells                      Fargo Bank, National Association, as Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| (f)                                     |     First                    American Real Estate Solutions of Texas, L.P., as sub-contractor for                    Aurora Loan Services LLC                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| (g)                                     |     Newport                    Management Corporation, as sub-contractor for Aurora Loan Services                    LLC                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| (h)                                     |     PHH                    Mortgage Corporation, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| (i)                                     |     IndyMac                    Bank, FSB, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| (j)                                |     Newport                    Management Corporation, as sub-contractor for IndyMac Bank,                    FSB                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| (k)                                     |     Aurora                    Loan Services LLC, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| 34                                      | Attestation                    report on                    assessment of compliance with servicing criteria for asset-backed                    securities                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| (a)                                     |     Aurora                      Loan Services LLC, as Master Servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| (b)                                     |     LaSalle                      Bank National Association, as Trustee, payinge agent and                      Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| (c)                                     |     Deutsche                      Bank                      National Trust Company, as Custodian and as subcontractor for                      IndyMac                      Bank, FSB                                                                                                                                                                                                                                                                                                                                                                                                    |
| (d)                                     |     US                      Bank                      National Association, as Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| (e)                                     |     Wells                      Fargo Bank, National Association, as Custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| (f)                                     |     First                    American Real Estate Solutions of Texas, L.P., as sub-contractor for                    Aurora Loan Services LLC                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| (g)                                     |     Newport                    Management Corporation, as sub-contractor for Aurora Loan Services                    LLC                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| (h)                                     |     PHH                    Mortgage Corporation, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| (i)                                     |     IndyMac                    Bank, FSB, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| (j)                                     |     Newport                    Management Corporation, as sub-contractor for IndyMac Bank,                    FSB                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| (k)                                     |     Aurora                    Loan                    Services LLC, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 35                                      | Servicer                    compliance                    statement                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| (a)                                     |     Aurora                      Loan Services LLC, as Master Servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| (b)                                     |     PHH                    Mortgage Corporation, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| (c)                                     |     IndyMac                    Bank,                    FSB, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| (d)                                     |     Aurora                    Loan                    Services LLC, as servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |