In enzymology, a dolichyldiphosphatase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are dolichyl diphosphate and H<sub>2</sub>O, whereas its two products are dolichyl phosphate and phosphate.
This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is dolichyl-diphosphate phosphohydrolase. Other names in common use include dolichol diphosphatase, dolichyl pyrophosphatase, dolichyl pyrophosphate phosphatase, dolichyl diphosphate phosphohydrolase, and Dol-P-P phosphohydrolase. This enzyme participates in n-glycan biosynthesis.