Exhibit 1

JOINT FILING AGREEMENT

In accordance with the Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including attachments thereto) with respect to the Class A Common Stock, par value $0.001 per share, of StepStone Group Inc., and further agree that this Joint Filing Agreement be included as an exhibit to such joint filings. In evidence thereof, each of the undersigned hereby executes this Joint Filing Agreement as of September 21, 2020.

This Agreement may be executed in two or more counterparts, each of which shall be deemed an original but all of which together will constitute one and the same instrument.

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IN WITNESS WHEREOF, the undersigned hereby executed this Joint Filing Agreement as of September 21, 2020.

/s/ Jennifer Ishiguro, Attorney-in-Fact

Monte M. Brem

/s/ Jennifer Ishiguro, Attorney-in-Fact

Scott W. Hart

/s/ Jennifer Ishiguro, Attorney-in-Fact

Jason P. Ment

/s/ Jennifer Ishiguro, Attorney-in-Fact

Jose A. Fernandez

/s/ Jennifer Ishiguro, Attorney-in-Fact

Johnny D. Randel

/s/ Jennifer Ishiguro, Attorney-in-Fact

Michael I. McCabe

/s/ Jennifer Ishiguro, Attorney-in-Fact

Mark Maruszewski

/s/ Jennifer Ishiguro, Attorney-in-Fact

Thomas Keck

/s/ Jennifer Ishiguro, Attorney-in-Fact

Thomas Bradley

/s/ Jennifer Ishiguro, Attorney-in-Fact

David Jeffrey

/s/ Jennifer Ishiguro, Attorney-in-Fact

Darren Friedman

Signature Page to Joint Filing Agreement