Exhibit 23.1
Consent of Independent Registered Public Accounting Firm
We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the Mimecast Limited 2015 Share Option and Incentive Plan of our report dated May 26, 2017, with respect to the consolidated financial statements of Mimecast Limited included in its Annual Report (Form 20-F) for the year ended March 31, 2017, filed with the Securities and Exchange Commission.
/s/ Ernst & Young LLP
Boston, Massachusetts
May 26, 2017
