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):

August 6, 2015

Eagle Materials Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number including area code: (214) 432-2000

Not Applicable

(Former name or former address if changed from 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:

Item 5.03. Amendment to Bylaws.

On August 6, 2015, the Board of Directors of Eagle Materials Inc. (the “Company”) amended the Company’s Amended and Restated Bylaws to add a forum selection provision for the adjudication of certain disputes. The new provision, set forth in new Section 9.4, provides that, unless the Company consents in writing to the selection of an alternative forum, the sole and exclusive forum for (i) any internal corporate claims within the meaning of the Delaware General Corporation Law (“DGCL”), as well as (ii) (A) any derivative action or proceeding brought on behalf of the Company, (B) any action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee of the Company to the Company or the Company’s stockholders, (C) any action asserting a claim arising pursuant to any provision of the DGCL, or (D) any action asserting a claim governed by the internal affairs doctrine, shall be a state or federal court located within the state of Delaware, in all cases subject to the court’s having personal jurisdiction over the indispensable parties named as defendants.

The above description is qualified in its entirety by reference to the amendment filed as Exhibit 3.1 hereto and incorporated herein by reference.

Item 5.07. Submission of Matters to a Vote of Security Holders.

The Company held its Annual Meeting of Stockholders on August 6, 2015. At the Annual Meeting, F. William Barnett, Richard Beckwitt, Ed H. Bowman and David W. Quinn were elected to the Board of Directors by the holders of the Company’s Common Stock, par value $0.01 per share, to serve until the 2018 Annual Meeting of Stockholders. The Company’s stockholders also approved an advisory resolution regarding the compensation of the Company’s named executive officers, as well as the expected appointment by the Company’s Board of Directors of Ernst & Young LLP as the Company’s independent auditors for the fiscal year ending March 31, 2016. Voting results for the director nominees and the other proposals are summarized below:

Election of Class III Directors

Robert L. Clarke, Martin M. Ellen and Steven R. Rowley continue to serve as directors with a term expiring in 2016. Laurence E. Hirsch, Michael R. Nicolais and Richard R. Stewart continue to serve as directors with a term expiring in 2017.

Approval of an advisory resolution regarding the compensation of the Company’s named executive officers

Approval of Ernst & Young LLP as the Independent Auditors

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: August 7, 2015

EXHIBIT INDEX