Exhibit 5.1

Wilson Sonsini Goodrich & Rosati
Professional Corporation 650 Page Mill Road
Palo Alto, CA 94304-1050 o: 650.493.9300
f: 650.493.6811

August 10, 2021

Nautilus Biotechnology, Inc.

425 Pontius Ave N, Ste 202

Seattle, Washington 98109

Re:Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Nautilus Biotechnology, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission on or about the date hereof, in connection with the registration under the Securities Act of 1933, as amended, of an aggregate of 24,447,730 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”), consisting of (i) 15,027,511 shares of Common Stock reserved for future issuance under the Company’s 2021 Equity Incentive Plan (the “2021 Plan”), (ii) 1,195,308 shares of Common Stock which are subject to currently outstanding stock options under the 2021 Plan, (iii) 1,244,900 shares of Common Stock reserved for issuance under the Company’s 2021 Employee Stock Purchase Plan, and (iv) 7,010,011 shares of Common Stock which are subject to currently outstanding stock options under the Company’s 2017 Equity Incentive Plan, as amended. As the Company’s legal counsel, we have reviewed the actions proposed to be taken by the Company in connection with the issuance and sale of the Shares to be issued under such plans (which plans are referred to herein as the “Plans”).

It is our opinion that the Shares, when issued and sold in the manner referred to in the Plans and pursuant to the agreements that accompany the Plans, will be legally and validly issued, fully paid and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement, and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

Very truly yours,

WILSON SONSINI GOODRICH & ROSATI,

Professional Corporation

/s/ Wilson Sonsini Goodrich & Rosati, P.C.

AUSTIN        BEIJING       BOSTON       BRUSSELS       HONG KONG        LONDON        LOS ANGELES        NEW YORK        PALO ALTO
SAN DIEGO       SAN FRANCISCO       SEATTLE       SHANGHAI       WASHINGTON, DC       WILMINGTON, DE