UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

For the Fiscal Year Ended December 31, 2011

OR

For the Transition Period from              to             

001-34809

Commission File Number

GLOBAL INDEMNITY PLC

(Exact name of registrant as specified in its charter)

ARTHUR COX BUILDING

EARLSFORT TERRACE

DUBLIN 2

IRELAND

(Address of principal executive office including zip code)

Registrant’s telephone number, including area code: 353 (0) 1 618 0517

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  ¨    NO  x

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.  ¨

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 the definitions 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

The aggregate market value of the common equity held by non-affiliates of the registrant, computed by reference to the price of the registrant’s Class A Ordinary shares as of the last business day of the registrant’s most recently completed second fiscal quarter (based on the last reported sale price on the Nasdaq Global Select Market as of such date), was $364,838,132. Class A ordinary shares held by each executive officer and director and by each person who is known by the registrant to beneficially own 5% or more of the registrant’s outstanding Class A ordinary shares have been excluded in that such persons may be deemed affiliates. The determination of affiliate status is not necessarily a conclusive determination for other purposes.

As of March 9, 2012, the registrant had outstanding 16,474,915 Class A Ordinary shares and 12,061,370 Class B Ordinary shares.

Explanatory Note

Global Indemnity plc (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment”) to amend its Annual Report on Form 10-K for the year ended December 31, 2011, filed with the Securities and Exchange Commission (the “SEC”) on March 14, 2012 (the “Initial 10-K Filing”), for the purpose of modifying Part IV Item 15, “Exhibits, Financial Statement Schedules” by amending and restating the Exhibit Index included in the Initial 10-K Filing to include the following exhibits:

In addition, pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, new certifications by our principal executive officer and principal financial officer are filed as Exhibits 31.3 and 31.4, respectively, to this Amendment.

Except for the corrections described above, this Amendment does not modify any disclosures contained in the Initial 10-K Filing. Additionally, this Amendment does not attempt to update the disclosures in our Initial 10-K Filing or to discuss any developments subsequent to the date of the Initial 10-K filing. In accordance with the rules and regulations of the SEC, the information contained in the Initial 10-K Filing and this Amendment is subject to updated or supplemental information contained in reports filed by us with the SEC subsequent to the filing dates of the Initial 10-K Filing and this Amendment.

PART IV

The agreements and other documents filed as exhibits to this report are not intended to provide factual information or other disclosure other than with respect to the terms of the agreements or other documents themselves, and you should not rely on them for that purpose. In particular, any representations and warranties made by us in these agreements or other documents were made solely within the specific context of the relevant agreement or document and may not describe the actual state of affairs as of the date they were made or at any other time.

The following documents are filed as part of this report:

SIGNATURES

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