EX-5.1

Exhibit 5.1

Goodwin Procter LLP

100 Northern Avenue
Boston, MA 02210

goodwinlaw.com

+1 617 570 1000

+1 617 523 1231

February 15, 2019

HubSpot, Inc.

25 First Street, 2nd Floor

Cambridge, MA 02141

Re:

Securities Registered under Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as counsel to you in connection with your filing of an automatic shelf registration statement on Form S-3 (File No. 333-229641) (as amended or supplemented, the “Registration Statement”) filed on February 13, 2019 with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), by HubSpot, Inc., a Delaware corporation (the “Company”). The Registration Statement became effective upon filing on February 13, 2019. Reference is made to our opinion letter dated February 13, 2019 and included as Exhibit 5.1 to the Registration Statement. We are delivering this supplemental opinion letter in connection with the prospectus supplement (the “Prospectus Supplement”) dated as of February 14, 2019 and filed on February 15, 2019 by the Company with the Commission pursuant to Rule 424(b)(5) under the Securities Act. The Prospectus Supplement relates to the offering by the Company of up to 2,150,500 shares of the Company’s common stock, par value $0.001 per share (the “Shares”) covered by the Registration Statement. The Shares include an over-allotment option granted to the underwriters of the offering to purchase 280,500 Shares. The Shares are being sold to the several underwriters named in, and pursuant to, an underwriting agreement among the Company and such underwriters, dated February 13, 2019 (the “Underwriting Agreement”).

We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinion set forth below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinion set forth below, on certificates of officers of the Company.

The opinion set forth below is limited to the Delaware General Corporation Law.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, upon issuance and delivery against payment therefor in accordance with the terms of the Underwriting Agreement, will be validly issued, fully paid and non-assessable.