Simpson Thacher & Bartlett llp

2475 Hanover Street

Palo Alto, CA 94304

telephone: +1-650-251-5000

facsimile: +1-650-251-5002

Direct Dial Number +1-650-251-5110 E-mail Address wbrentani@stblaw.com

via edgar November 15, 2021

Re: Acceleration Request for Certara, Inc.
Registration Statement on Form S-1 (File No. 333-261082)

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, as amended, we attach the requests of our client, Certara, Inc., and of the underwriters that effectiveness of the above-referenced Registration Statement be accelerated to 4:30 p.m., Eastern Time, on November 17, 2021, or as soon as possible thereafter.

Call me at (650) 251-5110 with any questions.

Very truly yours,

/s/ William B. Brentani

William B. Brentani

New York BEIJING HONG KONG Houston LONDON Los Angeles SÃO PAULO TOKYO Washington, D.C.

November 15, 2021

VIA EDGAR

Re: Certara, Inc.

Registration Statement on Form S-1

File No. 333-261082

Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, as amended, Certara, Inc. (the “Company”) hereby requests that the effective date of the above-referenced Registration Statement be accelerated so that it may become effective at 4:30 p.m., Eastern Time, on November 17, 2021, or as soon as possible thereafter. In this regard, the Company is aware of its obligations under the Securities Act.

If you require any additional information with respect to this letter, please contact William Brentani (650-251-5110) of Simpson Thacher & Bartlett LLP.

[Signature Page Follows]

Very truly yours,
CERTARA, INC.
By:	/s/ Richard M. Traynor
	Name:	Richard M. Traynor
	Title:	Senior Vice President and General Counsel

[Signature Page to Acceleration Request]

November 15, 2021

VIA EDGAR

Re:	Acceleration Request for Certara, Inc.
	Registration Statement on Form S-1 (File No. 333-261082)

Division of Corporation Finance

Securities and Exchange Commission

100 F Street, N.E.
Washington, D.C. 20549

Ladies and Gentlemen:

Pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), and as representatives of the several underwriters of the proposed public offering of Certara, Inc.’s common stock, we wish to advise you that we hereby join Certara, Inc.’s request that the effective date of the above-referenced Registration Statement be accelerated so that it may become effective at 4:30 p.m., Eastern time, on November 17, 2021, or as soon as possible thereafter.

Pursuant to Rule 460 under the Act, we, as representatives of the several underwriters, wish to advise you that there will be distributed to each underwriter or dealer who is reasonably anticipated to participate in the distribution of the securities, as many copies of the proposed form preliminary prospectus as appears to be reasonable to secure adequate distribution of the preliminary prospectus.

We, the undersigned, as representatives of the several underwriters, have complied and will continue to comply, and we have been informed by the participating underwriters that they have complied and will continue to comply, with the 48-hour requirement of Rule 15c2-8(b) under the Securities Exchange Act of 1934, as amended.

[Signature Page Follows]

Very truly yours,

JEFFERIES LLC

MORGAN STANLEY & CO. LLC

As the representatives of the several underwriters

JEFFERIES LLC

By:	/s/ Michael Gerardi
	Name:	Michael Gerardi
	Title:	Managing Director

MORGAN STANLEY & CO. LLC

By:	/s/ Kalli Dircks
	Name:	Kalli Dircks
	Title:	Managing Director

[Signature Page to Underwriters’ Acceleration Request]