UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): April 21, 2011

ALCOA INC.

(Exact name of Registrant as specified in its charter)

Office of Investor Relations 212-836-2674

Office of the Secretary 212-836-2732

(Registrant’s telephone number, including area code)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Registrant under any of the following provisions:

On April 21, 2011, Alcoa Inc. (“Alcoa”) issued and sold $1,250,000,000 aggregate principal amount of 5.40% Notes due 2021 (the “2021 Notes”) under the Indenture dated as of September 30, 1993 between Alcoa and The Bank of New York Mellon Trust Company, N.A., as successor in interest to J. P. Morgan Trust Company, N.A. (formerly known as Chase Manhattan Trust Company, National Association, as successor to PNC Bank, National Association), as trustee (the “Trustee”), as supplemented by the First Supplemental Indenture dated as of January 25, 2007 between Alcoa and the Trustee, the Second Supplemental Indenture dated as of July 15, 2008 between Alcoa and the Trustee, and the Third Supplemental Indenture dated as of March 24, 2009 between Alcoa and the Trustee. The 2021 Notes were sold pursuant to Alcoa’s effective shelf registration statement on Form S-3ASR (File No. 333-172327) filed on February 18, 2011 and the related Prospectus dated February 18, 2011, as supplemented by the Prospectus Supplement dated April 13, 2011 relating to the 2021 Notes. The form of the 2021 Notes is attached hereto as Exhibit 4 and is incorporated herein by reference. A copy of the opinion of counsel of Alcoa relating to the validity of the 2021 Notes is attached hereto as Exhibit 5 and is incorporated herein by reference.

On April 21, 2011, Alcoa issued a press release announcing the preliminary results of its tender offer to purchase for cash any and all of its 5.375% Notes due 2013 (the “5.375% Notes”) and the extension of the previously announced early tender date for the 5.375% Notes to coincide with the final expiration of the tender offer. A copy of the press release is attached hereto as Exhibit 99 and is incorporated herein by reference.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: April 21, 2011

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EXHIBIT INDEX

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