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 on FormS-3 and related Prospectus of Alector, Inc. for the registration of common stock, preferred stock, debt securities, warrants, purchase contracts, and units and to the incorporation by reference therein of our report dated March 24, 2020, with respect to the consolidated financial statements of Alector, Inc. included in its Annual Report (Form10-K) for the year ended December 31, 2019, filed with the Securities and Exchange Commission.
/s/ Ernst & Young LLP
San Jose, California
May 13, 2020