Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

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

THE SECURITIES EXCHANGE ACT OF 1934

For The Fiscal Year Ended December 31, 2006

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)

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 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.  [ü]

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer” and “large accelerated filer” 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 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 $28 billion. As of February 12, 2007, there were 869,536,783 shares of common stock, par value $1.00 per share, of the registrant outstanding.

Documents incorporated by reference.

Parts I, II and IV of this Form 10-K incorporate by reference certain information from the registrant’s 2006 Annual Report to Shareholders (Annual Report). Part III of this Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2007 Annual Meeting of Shareholders filed or to be filed pursuant to Regulation 14A (Proxy Statement).

Table of Contents

TABLE OF CONTENTS

Note on Incorporation by Reference

In this Form 10-K, selected items of information and data are incorporated by reference to portions of the Annual Report and Proxy Statement. Unless otherwise provided herein, any reference in this report to disclosures in the Annual Report or Proxy Statement shall constitute incorporation by reference of that specific disclosure into this Form 10-K.

Table of Contents

ALCOA INC.

Formed in 1888, Alcoa Inc. is a Pennsylvania corporation with its principal office in New York, New York. In this report, unless the context otherwise requires, “Alcoa” or the “company” means Alcoa Inc. and all subsidiaries consolidated for the purposes of its financial statements.

The company’s Internet address is http://www.alcoa.com. Alcoa makes available free of charge on or through its website its annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 as soon as reasonably practicable after the company electronically files such material with, or furnishes it to, the Securities and Exchange Commission (SEC). The SEC maintains an Internet site that contains these reports at http://www.sec.gov.

PART I

Item 1.     Business.

Description of the Business

Information describing Alcoa’s businesses can be found in the Annual Report at the indicated pages:

Overview

Alcoa is the world’s leading producer of primary aluminum, fabricated aluminum, and alumina, and is active in all major aspects of the industry: technology, mining, refining, smelting, fabricating, and recycling. Aluminum is a commodity that is traded on the London Metal Exchange (LME) and priced daily based on market supply and demand. Aluminum and alumina represent approximately three-fourths of Alcoa’s revenues, and the price of aluminum influences the operating results of Alcoa. Nonaluminum products include precision castings, industrial fasteners, consumer products, food service and flexible packaging products, plastic closures, and electrical distribution systems

3

Table of Contents

for cars and trucks. Alcoa’s products are used worldwide in aircraft, automobiles, commercial transportation, packaging, consumer products, building and construction, and industrial applications.

Alcoa is a global company operating in 44 countries. North America is the largest market with 59% of Alcoa’s revenues. Europe is also a significant market with 24% of the company’s revenues. In addition, Alcoa has investments and activities in Australia, Brazil, China, Iceland, Jamaica and Russia which present opportunities for substantial growth. Governmental policies and other economic factors, including inflation and fluctuations in foreign currency exchange rates and interest rates, affect the results of operations in these countries.

Alcoa’s operations consist of six worldwide segments: Alumina, Primary Metals, Flat-Rolled Products, Extruded and End Products, Engineered Solutions, and Packaging and Consumer.

The Alumina segment primarily consists of a series of affiliated operating entities referred to as Alcoa World Alumina and Chemicals (AWAC). Generally, Alcoa owns 60% and Alumina Limited owns 40% of these individual entities. For more information on AWAC, see Exhibit Nos.10 (a) through 10(f) to this report.

Bauxite Interests

Aluminum is one of the most plentiful elements in the earth’s crust. Aluminum is produced primarily from bauxite, an ore containing aluminum in the form of aluminum oxide, commonly referred to as alumina. Aluminum is made by extracting alumina from bauxite and then removing oxygen from the alumina. Alcoa processes most of the bauxite that it mines into alumina. The company obtains bauxite from reserves held by AWAC, from the company’s interests in the countries listed in the chart below, and under both long-term and short-term contracts and mining leases. In 2006, Alcoa consumed 33.9 million metric tons (mt) of bauxite from its own reserves, 6.6 million mt from related third parties and 3.1 million mt from unrelated third parties. Alcoa’s present sources of bauxite are sufficient to meet the forecasted requirements of its alumina refining operations for the foreseeable future. The following table provides information regarding the company’s bauxite interests:

Alcoa Active Bauxite Interests¹

4

Table of Contents

Alumina Refining Facilities and Capacity

Alcoa is the world’s leading producer of alumina. Alcoa’s alumina refining facilities and its worldwide alumina capacity are shown in the following table:

Alcoa Worldwide Alumina Refining Capacity

5

Table of Contents

In January 2005, Alcoa and the Government of the Republic of Ghana announced the signing of a Memorandum of Understanding (MOU), under which the parties would evaluate the possible development of an integrated aluminum industry in Ghana, including bauxite mining, alumina refining, aluminum production, and rail transportation infrastructure upgrades. Alcoa has worked with the Government to conduct feasibility studies related to the bauxite resources. The parties expect to continue discussions during 2007 on the feasibility of the project.

In September 2005, Alcoa announced that its Board of Directors approved plans to make further investments in the company’s Brazilian “upstream” operations, including a 2.1 million mtpy expansion of the Alumar consortium alumina refinery in São Luís, state of Maranhao (expected to increase the refinery’s capacity from 1.4 million mtpy to approximately 3.5 million mtpy beginning in late 2008, with Alcoa’s share of the total facility output more than doubling to 1.89 million mtpy based on its 54% ownership stake through AWAC) and the modernization of the Poços de Caldas aluminum smelter, in the state of Minas Gerais.

In November 2005, AWA LLC and Alcan announced the signing of a Basic Agreement with the Government of Guinea that sets forth the framework for development of a 1.5 million mtpy alumina refinery in Guinea. The Basic Agreement was approved by the Guinean National Assembly in May of 2006 and was promulgated into law by decree of the President of Guinea in July of 2006.

In April 2006, AWAC signed an MOU with Vietnam National Coal-Minerals Industries Group (Vinacomin) under which the parties will explore the feasibility of creating a joint venture to develop a bauxite mine and alumina refinery in the Dak Nong province of Vietnam. If established, the joint venture would be 51% owned by Vinacomin and 49% owned by AWAC.

In September 2006, Alcoa received environmental approval from the Government of Western Australia for expansion of the Wagerup alumina refinery to a maximum capacity of 4.7 million mtpy, a potential increase of over 2 million mtpy. This approval includes a variety of environmental conditions that must be satisfied before Alcoa can seek construction approval for the project. The environmental approval paves the way for Alcoa to proceed to the next stage of project design (feasibility study) following completion of pre-feasibility work scheduled for the first half of 2007.

The 1.5 million mtpy planned expansion of the Jamalco alumina refinery in Clarendon, Jamaica is subject to supply of natural gas by the Government of Jamaica and acceptable market conditions. The Government of Jamaica continues to negotiate with third party suppliers to procure natural gas to be supplied to Jamalco, but no final agreement has been reached. Alcoa is proceeding with the Early Works Program, which will add 146,000 mtpy of production to Jamalco, bringing the total capacity to 1.420 million mtpy. The Early Works Program is expected to be substantially complete by the end of the first quarter of 2007. As a result of the Early Works Program, Alcoa’s ownership in Jamalco will increase to approximately 55%, with the Government of Jamaica owning approximately 45%.

6

Table of Contents

Primary Aluminum Facilities and Capacity

The company’s primary aluminum smelters and their respective capacities are shown in the following table:

Alcoa Worldwide Smelting Capacity