UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K/A

(Amendment No. 1)

FOR ANNUAL AND TRANSITION REPORTS

PURSUANT TO SECTIONS 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

(Mark One)

For the fiscal year ended December 31, 2011

For the transition period from                     to                    

Commission file number: 1-32381

HERBALIFE LTD.

(Exact Name of Registrant as Specified in Its Charter)

(213) 745-0500

(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  þ        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  þ

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  þ        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  þ        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 the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

(Do not check if a smaller reporting company)

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

There were 116,273,652 common shares outstanding as of February 15, 2012. The aggregate market value of the Registrant’s common shares held by non-affiliates was approximately $5,688 million as of June 30, 2011, based upon the last reported sales price on the New York Stock Exchange on that date of $57.64.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Definitive Proxy Statement to be filed with the Securities and Exchange Commission no later than 120 days after the end of the Registrant’s fiscal year ended December 31, 2011, are incorporated by reference in Part III of this Annual Report on Form 10-K.

EXPLANATORY NOTE

This Amendment No. 1 to the Annual Report on Form 10-K/A of Herbalife Ltd. (the “Company”) for the fiscal year ended December 31, 2011 is being filed solely to furnish the XBRL exhibits noted in the Exhibit Index hereto as furnished, not filed, herewith, which were incomplete in the initial filing of the Company’s Annual Report on Form 10-K on February 21, 2012 (the “Original Filing”) due to an XBRL processing error. This amendment does not otherwise change or update the disclosure set forth in the Original Filing or otherwise reflect events occurring after the date thereof.

EXHIBIT INDEX

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, thereto duly authorized.

HERBALIFE LTD.

Dated: April 11, 2012