Exhibit 16.1

March 1, 2021

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Ladies and Gentlemen:

We have read the section titled “Change in Accountants” of the Registration Statement on Form S-1 dated March 1, 2021, of SEMrush Holdings, Inc. and are in agreement with the statements contained in the first, third, fourth and fifth paragraphs therein. We have no basis to agree or disagree with other statements of the registrant contained therein.

/s/ Ernst & Young LLC

Moscow, Russian Federation