UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D. C. 20549

FORM 10-K/A

Amendment No. 1

For the fiscal year ended December 31, 2011.

OR

Commission file number 0-13089

Hancock Holding Company

(Exact name of registrant as specified in its charter)

(228) 868-4727

Registrant’s telephone number, including area code

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

NONE

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

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

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” 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

The aggregate market value of the voting stock held by nonaffiliates of the registrant as of December 31, 2011 was $2.6 billion based upon the closing market price on NASDAQ on June 30, 2011. For purposes of this calculation only, shares held by nonaffiliates are deemed to consist of (a) shares held by all shareholders other than directors and executive officers of the registrant plus (b) shares held by directors and officers as to which beneficial ownership has been disclaimed.

On February 1, 2012, the registrant had outstanding 84,749,038 shares of common stock for financial statement purposes.

EXPLANATORY NOTE

Hancock Holding Company is filing this Amendment No. 1 on form 10-K/A to its Annual Report on Form 10-K for the year ended December 31, 2011 for the sole purposes of furnishing XBRL interactive data files. The original Form 10-K was filed with the Securities and Exchange Commission on February 28, 2012.

No other changes have been made to the Form 10-K. This Form 10-K/A speaks as of the original filing data of the Form 10-K, does not reflect events that may have occurred subsequent to the filing date, and does not modify or update in any way disclosures made in the Form 10-K.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the definitive Proxy Statement for the Registrant’s Annual Meeting of Shareholders to be filed with the Securities and Exchange Commission are incorporated by reference into Part III of this report.

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.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Registrant and in the capacities and on the dates indicated.