In enzymology, a D-glutaminase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are D-glutamine and H<sub>2</sub>O, whereas its two products are D-glutamate and NH<sub>3</sub>.
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is D-glutamine amidohydrolase. This enzyme participates in d-glutamine and d-glutamate metabolism and nitrogen metabolism.