Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We have issued our reports dated February 27, 2015, with respect to the consolidated financial statements and internal control over financial reporting in the Annual Report of AAON, Inc. on Form 10-K for the year ended December 31, 2014. We hereby consent to the incorporation by reference of said reports in the Registration Statements of AAON, Inc. on Forms S-8 (File No. 333-52824 and File No. 333-151915).

/s/ GRANT THORNTON LLP

Tulsa, Oklahoma

February 27, 2015