Exhibit 23.3
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We hereby consent to the incorporation by reference in this Registration Statement on FormS-3 of Ultragenyx Pharmaceutical Inc. of our report dated March 9, 2017 relating to the financial statements, which appears in Dimension Therapeutics Inc.’s Annual Report on Form 10-K for the year ended December 31, 2016. We also consent to the reference to us under the heading “Experts” in such Registration Statement.
/s/ PricewaterhouseCoopers LLP
Boston, Massachusetts
February 21, 2018
