Exhibit 23.1
Consent of Independent Registered Public Accounting Firm
We consent to the incorporation by reference in Registration Statement (Nos. 333-62331 and 333-26587) on Form S-8 of Glatfelter Corporation of our report dated June 24, 2021 relating to our audit of the financial statements and supplemental schedule of the Glatfelter 401(k) Savings Plan, which appears in this Annual Report on Form 11-K of Glatfelter 401(k) Savings Plan for the year ended December 31, 2020.
/s/ Insero & Co. CPAs, LLP
Certified Public Accountants
Rochester, New York
June 24, 2021