Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the use in this Registration Statement on Form S-1 of SQZ Biotechnologies Company of our report dated July 20, 2020, except for the effects of the stock split discussed in Note 18 to the consolidated financial statements, as to which the date is October 26, 2020, relating to the financial statements of SQZ Biotechnologies Company, which appears in this Registration Statement. We also consent to the reference to us under the heading “Experts” in such Registration Statement.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

February 9, 2021