Exhibit 23

Consent of Independent Registered Public Accounting Firm

The Plan Administrator

Clayton Williams Energy, Inc. 401(k) Plan and Trust:

We consent to the incorporation by reference in the Registration Statement (No. 33-69688) on Form S-8 of Clayton Williams Energy, Inc. of our report dated June 12, 2014, relating to our audit of the financial statements and the financial statement schedule, which appear in this Annual Report on Form 11-K of Clayton Williams Energy, Inc. 401(k) Plan and Trust for the years ended December 31, 2013 and 2012.

/s/ Hein & Associates LLP

June 12, 2014

Dallas, Texas