UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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): December 9, 2014

Concert Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (781) 860-0045

(Former Name or Former Address, if Changed Since 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 (see General Instruction A.2. below):

On December 9, 2014, the Board of Directors (the “Board”) of Concert Pharmaceuticals, Inc. (the “Company”) elected Thomas Auchincloss to serve as a class III director until the Company’s 2017 Annual Meeting of Stockholders and thereafter until his successor is duly elected and qualified. Mr. Auchincloss will serve as the Chairperson for the Audit Committee of the Board.

Mr. Auchincloss will receive compensation for his board service as a non-employee director in accordance with the Company’s previously disclosed director compensation program, including a one-time nonqualified stock option that will be granted to Mr. Auchincloss at the Board meeting on December 11, 2014 under the Company’s 2014 Stock Incentive Plan to purchase 25,000 shares of the Company’s common stock, par value $0.001 per share (the “Common Stock”), with an exercise price equal to the closing price of the Common Stock on the NASDAQ Global Market on the grant date. The option will vest in equal quarterly installments over a three-year period measured from the date of grant, subject to Mr. Auchincloss’ continued service as a director, and will become exercisable in full upon a change in control of the Company.

In addition, on December 9, 2014, Mr. Auchincloss entered into an indemnification agreement (the “Indemnification Agreement”) with the Company. The Indemnification Agreement is substantially identical to the form of indemnification agreement that the Company has entered into with its other directors and provides that the Company will indemnify Mr. Auchincloss for some expenses, including attorneys’ fees, judgments, fines and settlement amounts incurred by him in any action or proceeding arising out of his service as one of the Company’s directors.

The foregoing description of the Indemnification Agreement is qualified in its entirety by the full text of the form of indemnification agreement by and between the Company and each of its officers and directors, which is incorporated herein by reference to Exhibit 10.13 to the Company’s Registration Statement on Form S-1 (File No. 333-193335), filed with the Securities and Exchange Commission on January 13, 2014.

The Exhibits to this Current Report on Form 8-K are listed in the Exhibit Index attached hereto.

SIGNATURE

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