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SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K/A

(Mark One)

For the fiscal year Ended December 31, 2011

or

Commission File Number 0-26850

FIRST DEFIANCE FINANCIAL CORP.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (419) 782-5015

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

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

None

(Title of Class)

Indicate by check mark if the 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 checkmark whether the registrant has submitted electronically and posted on its corporate Website, 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 definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

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

As of February 29, 2012, there were issued and outstanding 9,726,454 shares of the Registrant’s common stock.

The aggregate market value of the voting stock held by non-affiliates of the Registrant computed by reference to the average bid and ask price of such stock as of June 30, 2011 was approximately $137.4 million.

Documents Incorporated by Reference

Part III of this Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for the 2012 Annual Shareholders’ Meeting.

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Explanatory Note

This Amendment No. 1 on Form 10-K/A (this “Amendment”) is being filed by First Defiance Financial Corp. (“First Defiance” or the “Company”) to amend its Annual Report on Form 10-K for the year ended December 31, 2011, filed with the Securities and Exchange Commission on March 7, 2012 (the “Original 10-K”). This Amendment is being filed to revise the referenced filing date of the Proxy Statement that is incorporated by reference in Part III, Items 10 and 11 and to revise the names of the sections referenced to match those in the Proxy Statement.

Except for the foregoing, the Original 10-K remains unchanged. This Amendment does not reflect any events that may have occurred subsequent to the filing date of the Original 10-K of March 7, 2012, nor does it modify or otherwise update in any way the disclosures made in the Original 10-K.

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First Defiance Financial Corp.

Amendment No. 1 on Form 10-K/A

Cross Reference Index

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PART III

The information required herein is incorporated by reference from the sections captioned: “Proposal 1 - Election of Directors,” “Executive Officers” and “Section 16(a) Beneficial Ownership Reporting Compliance” of the definitive proxy statement to be filed on or about March 26, 2012 (the “Proxy Statement”).

First Defiance has adopted a Code of Ethics applicable to all officers, directors and employees that complies with SEC requirements, and is available on its Internet site at www.fdef.com under the Investor Relations tab.

Information required by this item is set forth under the captions “Compensation Discussion and Analysis,” “Executive Compensation,” “2011 Director Compensation,” “Compensation Committee Report” and “Compensation Committee Interlocks and Insider Participation” of the Proxy Statement.

PART IV

The following documents are filed as Item 8 of this Form 10-K.

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SIGNATURES

Pursuant to the requirements of Sections 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 indicated on April 3, 2012.

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Exhibit Index

This report incorporates by reference the documents listed below that we have previously filed with the SEC. The SEC allows us to incorporate by reference information in this document. The information incorporated by reference is considered to be part of this document.

This information may be read and copied at the Public Reference Room of the SEC at 100 F Street, N.E., Washington D.C. 20549. The SEC also maintains an internet web site that contains reports, proxy statements, and other information about issuers, like First Defiance, who file electronically with the SEC. The address of the site is http://www.sec.gov. The reports and other information filed by First Defiance with the SEC are also available at the First Defiance Financial Corp. web site. The address of the site is http://www.fdef.com. Except as specifically incorporated by reference into this Annual Report on Form 10-K, information on those web sites is not part of this report.

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