Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 333-193683) of our report dated June 22, 2015, with respect to the Statements of Net Assets Available for Benefits of the Capital One Financial Corporation Associate Savings Plan as of December 31, 2014 and 2013 and the related Statements of Changes in Net Assets Available for Benefits for the years then ended, and the related supplemental Schedule H, Line 4i—Schedule of Assets (Held at End of Year) as of December 31, 2014, which reports appear in the December 31, 2014 Annual Report on Form 11-K of the Capital One Financial Corporation Associate Savings Plan.

/s/ Keiter, Stephens, Hurst, Gary & Shreaves, P.C.

Glen Allen, Virginia

June 22, 2015