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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K/A

(Amendment No. 2)

For the fiscal year ended December 31, 2010

OR

For the transition period from             to             

Commission file number: 001-32977

GMX RESOURCES INC.

(Exact name of registrant as specified in its charter)

(405) 600-0711

(Registrant’s telephone number, including area code)

Securities registered under Section 12(b) of the Exchange Act:

Securities registered under Section 12(g) of the Exchange Act:

None

Indicate by check mark if registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definition of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. Check one:

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act)    Yes  ¨    No  x

As of June 30, 2010, the aggregate market value of the registrant’s common stock held by non-affiliates was $186,431,169 based on the closing price of such common stock in the daily composite list of transactions on the New York Stock Exchange of $6.49.

As of March 10, 2011, there were 56,415,790 shares of the registrant’s common stock outstanding, including 2,640,000 shares under a share lending agreement that will be returned to the registrant upon conversion or maturity of certain outstanding convertible notes and 688,822 shares of unvested restricted stock.

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Explanatory Note

This Amendment No. 2 to the Annual Report on Form 10-K/A (this “Form 10-K/A”) amends the Annual Report on Form 10-K for the year ended December 31, 2010 of GMX Resources Inc. (“GMX”), which was filed with the Securities and Exchange Commission on March 11, 2011, as amended by Form 10-K/A filed on September 1, 2011 (the “Form 10-K”). This Form 10-K/A is being filed solely to file a revised reserve engineer reserve report of MHA Petroleum Consultants, Inc. for the year ended December 31, 2010 (which revised report does not contain any revisions to total proved reserves or estimated future net revenue). The registrant is hereby amending and replacing in its entirety the revised reserve engineer report of MHA Petroleum Consultants, Inc. for the year ended December 31, 2010 filed as Exhibit 99.1.

Except as described above, this Form 10-K/A does not amend, update or change any other items or disclosures in the Form 10-K for the year ended December 31, 2010, including any of the financial information disclosed in Parts II and IV of the Form 10-K, and does not purport to reflect any information or events subsequent to the filing thereof.

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GMX RESOURCES INC.

Form 10-K/A

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PART IV

The following documents are filed as part of this amendment:

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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EXHIBIT INDEX

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