Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption "Experts" in the Registration Statement (Form S-3) and related Prospectus of Xilio Therapeutics, Inc. for the registration of 17,580,566 shares of its common stock and to the incorporation by reference therein of our report dated April 1, 2024, with respect to the consolidated financial statements of Xilio Therapeutics, Inc. included in its Annual Report (Form 10-K) for the year ended December 31, 2023, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Boston, Massachusetts

April 30, 2024