Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of BlackLine, Inc. of our report dated February 25, 2022 relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in BlackLine, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2021.

/s/ PricewaterhouseCoopers LLP

Los Angeles, CA

February 25, 2022