Exhibit 23

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in Registration Statement Nos. 333-162890 and 333-253190 on Form S-8 of our report dated June 24, 2021, appearing in the Annual Report on Form 11-K of the ALLETE and Affiliated Companies Retirement Savings and Stock Ownership Plan for the year ended December 31, 2020.

/s/ Reilly, Penner & Benton LLP

Reilly, Penner & Benton LLP

Milwaukee, Wisconsin

July 23, 2021