Zendesk (ZEN) 10-K 2018 FY Annual report

EXHIBIT 23.1

Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the following Registration Statements:

(1) Registration Statement (Form S-8 No. 333-216280) pertaining to the Zendesk, Inc. 2014 Stock Option and Incentive Plan, and the Zendesk, Inc. 2014 Employee Stock Purchase Plan,

(2) Registration Statement (Form S-8 No. 333-209781) pertaining to the Zendesk, Inc. 2014 Stock Option and Incentive Plan, and the Zendesk, Inc. 2014 Employee Stock Purchase Plan,

(3) Registration Statement (Form S-8 No. 333-202137) pertaining to the Zendesk, Inc. 2014 Stock Option and Incentive Plan, and the Zendesk, Inc. 2014 Employee Stock Purchase Plan,

(4) Registration Statement (Form S-8 No. 333-195958) pertaining to the Zendesk, Inc. 2014 Stock Option and Incentive Plan, the Zendesk, Inc. 2014 Employee Stock Purchase Plan, and the Zendesk, Inc. 2009 Stock Option and Grant Plan;

(5) Registration Statement (Form S-8 No. 333-223162) pertaining to the Zendesk, Inc. 2014 Stock Option and Incentive Plan, and the Zendesk, Inc. 2014 Employee Stock Purchase Plan, and

(6) Registration Statement (Form S-3 ASR No. 333-223164) and related prospectus for the registration of debt securities, common stock, preferred stock, warrants, depositary shares, purchase contracts, guarantees, and units.

of our reports dated February 14, 2019, with respect to the consolidated financial statements of Zendesk, Inc. and the effectiveness of internal control over financial reporting of Zendesk, Inc. included in this Annual Report (Form 10-K) of Zendesk, Inc. for the year ended December 31, 2018.

/s/ Ernst & Young LLP

San Francisco, CA

February 14, 2019