UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K/A

(Amendment No. 1)

[ x ] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

For The Fiscal Year Ended December 31, 2011

OR

[    ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number 1-3610

ALCOA INC.

(Exact name of registrant as specified in its charter)

390 Park Avenue, New York, New York 10022-4608

(Address of principal executive offices)     (Zip code)

Registrant’s telephone numbers:

Investor Relations------------— (212) 836-2674

Office of the Secretary-------—(212) 836-2732

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 ü  No     .

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

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, and (2) has been subject to such filing requirements for the past 90 days.  Yes ü  No     .

Indicate by check mark 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.  Yes ü  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.

Large accelerated filer [ü]       Accelerated filer [    ]       Non-accelerated filer [     ]       Smaller reporting company [    ]

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

The aggregate market value of the outstanding common stock, other than shares held by persons who may be deemed affiliates of the registrant, as of the last business day of the registrant’s most recently completed second fiscal quarter was approximately $17 billion. As of February 10, 2012, there were 1,066,107,670 shares of common stock, par value $1.00 per share, of the registrant outstanding.

Documents incorporated by reference.

Part III of this Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2012 Annual Meeting of Shareholders to be filed pursuant to Regulation 14A (Proxy Statement).

Explanatory Note

Alcoa Inc. (the “Registrant”) is filing this Amendment No. 1 on Form 10-K/A (“Form 10-K/A”) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2011, filed with the Securities and Exchange Commission on February 16, 2012 (the “Original Filing”), for the sole purpose of inserting the conformed signatures of the applicable members of the Registrant’s Board of Directors on the power of attorney filed as Exhibit 24. Such conformed signatures were inadvertently omitted from the electronic version of Exhibit 24 filed with the Original Filing, although the Registrant had manually signed copies of the power of attorney in its possession when the Original Filing was made. This Form 10-K/A sets forth the complete text of (1) the exhibit listing in Part IV, Item 15. Exhibits, Financial Statement Schedules, section (a)(3) Exhibits, which is unchanged, and (2) Exhibit 24.

Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, this Form 10-K/A also contains new certifications pursuant to Section 302 of the Sarbanes-Oxley Act of 2002, which are attached hereto. Because no financial statements have been included in this Form 10-K/A and this Form 10-K/A does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have been omitted.

Except as described above, no other changes have been made to the Original Filing, and this Form 10-K/A does not modify, amend or update in any way any of the financial or other information contained in the Original Filing. This Form 10-K/A does not reflect events that may have occurred subsequent to the filing date of the Original Filing.

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Part IV

Item 15. Exhibits, Financial Statement Schedules.

(a)(3) Exhibits.

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4

5

6

7

8

9

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Amendments and modifications to other Exhibits previously filed have been omitted when in the opinion of the registrant such Exhibits as amended or modified are no longer material or, in certain instances, are no longer required to be filed as Exhibits.

No other instruments defining the rights of holders of long-term debt of the registrant or its subsidiaries have been filed as Exhibits because no such instruments met the threshold materiality requirements under Regulation S-K. The registrant agrees, however, to furnish a copy of any such instruments to the Commission upon request.

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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.

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