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 11, 2015

Continental Building Products, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (703) 480-3800

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:

Underwriting Agreement

On May 11, 2015, Continental Building Products, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with LSF8 Gypsum Holdings, L.P. (the “Selling Stockholder”) and Credit Suisse Securities (USA) LLC (the “Underwriter”) pursuant to which the Selling Stockholder agreed to sell to the Underwriter 4,600,000 shares of the Company’s common stock, par value $0.001 per share (“Common Stock”), at a price per share of $21.90 (the “Offering”). The Selling Stockholder also granted the Underwriter an option to purchase up to 690,000 additional shares of Common Stock held by the Selling Stockholder.

The Selling Stockholder will receive all net proceeds from the sale of Common Stock pursuant to the Underwriting Agreement. The Company will not receive any of the proceeds from the sale of Common Stock by the Selling Stockholder.

The Company made certain customary representations, warranties and covenants in the Underwriting Agreement concerning, among other things, its business and its Registration Statement on Form S-3, preliminary prospectus supplement and final prospectus supplement related to the Offering. The Company also agreed to indemnify the Underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended.

The foregoing description of the Underwriting Agreement is qualified in its entirety by reference to the complete text of the Underwriting Agreement, a copy of which is filed as Exhibit 1.1 hereto and incorporated by reference herein.

The Offering closed on May 15, 2015.

Stock Purchase Agreement

On May 11, 2015, the Company also entered into a stock purchase agreement (the “Stock Purchase Agreement”) with the Selling Stockholder providing for the repurchase by the Company, conditioned on the closing of the Offering, of a number of shares of Common Stock held by the Selling Stockholder with an aggregate value of approximately $20.0 million, at a price per share equal to the per share price paid by the Underwriter to the Selling Stockholder pursuant to the Underwriting Agreement (the “Repurchase”).

The Repurchase closed on May 15, 2015.

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.

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