Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

The Sonic Corp. Savings and Profit Sharing Plan Administrative Committee

Sonic Corp. Savings and Profit Sharing Plan:

We consent to the incorporation by reference in the registration statement (No. 333-26359) on Form S-8 of Sonic Corp. of our report dated June 25, 2018, with respect to the statements of net assets available for benefits of the Sonic Corp. Savings and Profit Sharing Plan as of December 31, 2017 and 2016, the related statement of changes in net assets available for benefits for the year ended December 31, 2017 and the related notes (collectively, the financial statements), and the supplemental schedule of schedule H, line 4i – schedule of assets (held at end of year) as of December 31, 2017, which report appears in the December 31, 2017 annual report for Form 11-K of the Sonic Corp. Savings and Profit Sharing Plan.

/s/ KPMG LLP

Oklahoma City, Oklahoma

June 25, 2018