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): May 21, 2013

WILLIAM LYON HOMES

(Exact name of registrant as specified in charter)

4695 MacArthur Court, 8^th Floor

Newport Beach, California 92660

(Address of principal executive offices and zip code)

(949) 833-3600

(Registrant’s telephone number, including area code)

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:

Warrant Amendment

On May 21, 2013, in connection with the filing of the Third Amended and Restated Certificate of Incorporation of William Lyon Homes (the “Company”) upon closing of the initial public offering (the “IPO”) of shares of the Class A Common Stock, par value $0.01 per share (“Class A Common Stock”), of the Company, and as described in the Form S-1 Registration Statement (File No. 333-187819) (the “Registration Statement”) declared effective by the Securities and Exchange Commission on May 15, 2013, the Company and the holder of the Company’s outstanding Warrant to Purchase Shares of Class B Common Stock, dated February 25, 2012 (the “Warrant”), entered into Amendment No. 1 to the Warrant (the “Warrant Amendment”). Pursuant to the Warrant Amendment, the Warrant was amended to extend the term from five years to ten years, and the Warrant will now expire on February 24, 2022. All other terms of the Warrant will remain in full force and effect.

The foregoing description of the Warrant Amendment is qualified in its entirety by reference to the Warrant Amendment, a copy of which is attached hereto as Exhibit 10.1 and is incorporated by reference herein.

Indemnification Agreements

On May 21, 2013, the Company entered into indemnification agreements (the “Indemnification Agreements”) with each of the Company’s executive officers and directors, an initial form of which had been filed as an exhibit to the Registration Statement. The Company’s current executive officers and inside directors are General William Lyon, Chairman of the Board of Directors and Executive Chairman, William H. Lyon, Director and Chief Executive Officer, Matthew R. Zaist, President and Chief Operating Officer, Colin T. Severn, Vice President, Chief Financial Officer and Corporate Secretary, Richard S. Robinson, Senior Vice President of Finance, Mary J. Connelly, Senior Vice President and Nevada Division President, W. Thomas Hickcox, Senior Vice President and Arizona Division President, Brian W. Doyle, Senior Vice President and California Region President, J. Eric Eckberg, Senior Vice President and Colorado Division President, and Maureen L. Singer, Vice President of Human Resources. The Company’s current outside directors are Douglas K. Ammerman, Michael Barr, Gary H. Hunt, Matthew R. Niemann, Nathaniel Redleaf and Lynn Carlson Schell.

Under the Indemnification Agreements, the Company has agreed to, among other things, indemnify these individuals against certain liabilities that may arise in connection with their status or service as one of the Company’s executive officers or directors or in their capacity at other specified entities at which they may serve at the Company’s request and to advance their expenses incurred as a result of any proceeding for which they may be entitled to indemnification. The Indemnification Agreements supersede all prior agreements between the parties with respect to the subject matter thereof, are intended to provide indemnification rights to the fullest extent permitted by the General Corporation Law of the State of Delaware (the “DGCL”) and are in addition to any other rights these individuals may have under the Company’s organizational documents or applicable law.

The foregoing description of the Indemnification Agreements is qualified in its entirety by reference to the form of Indemnification Agreement, a copy of which is attached hereto as Exhibit 10.2 and is incorporated by reference herein.

Third Amended and Restated Certificate of Incorporation

On May 21, 2013, in connection with and upon the closing of the Company’s IPO, and as described in the Registration Statement, the Company filed its Third Amended and Restated Certificate of Incorporation (the “Restated Charter”) with the Secretary of State of the State of Delaware, thereby giving effect to the Restated Charter as of May 21, 2013. Immediately prior to the filing of the Restated Charter, pursuant to the terms of the Company’s Second Amended and Restated Certificate of Incorporation, as amended (the “Previous Charter”), all outstanding shares of Class C Common Stock, par value $0.01 per share, Class D Common Stock, par value $0.01 per share (including shares underlying outstanding equity awards), and Convertible Preferred Stock, par value $0.01 per share, automatically converted into shares of Class A Common Stock on a one-for-one basis and as automatically adjusted for the

1-for-8.25 reverse stock split of the Company’s Class A Common Stock that occurred upon the pricing of the Company’s IPO.

The Restated Charter, among other things, amends and restates the Previous Charter to provide for the following:

The foregoing description of the Restated Charter is qualified in its entirety by reference to the full text of the Restated Charter, a copy of which is attached as Exhibit 3.1 and is incorporated herein by reference.

Amended and Restated Bylaws

On May 21, 2013, effective upon the Company’s filing of the Restated Charter with the Secretary of State of the State of Delaware, and as described in the Registration Statement, the Company’s existing Second Amended and Restated Bylaws (the “Previous Bylaws”) were further amended and restated (as so amended and restated, the “Amended and Restated Bylaws”) to, in part, incorporate certain public company governance provisions in connection with the IPO, update to reflect recent changes to the DGCL, and implement changes consistent with the Restated Charter.

The primary changes being implemented by the Amended and Restated Bylaws include, among others, the following:

The foregoing description of the Amended and Restated Bylaws is qualified in its entirety by reference to the full text of the Amended and Restated Bylaws, a copy of which is attached as Exhibit 3.2 and is incorporated herein by reference.

The following exhibits are incorporated by reference:

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.

EXHIBIT INDEX