In enzymology, a D-xylose 1-dehydrogenase (EC 1.1.1.175) is an enzyme that catalyzes the chemical reaction

D-xylose + NAD⁺ ${\displaystyle \rightleftharpoons }$ D-xylonolactone + NADH + H⁺

Thus, the two substrates of this enzyme are D-xylose and NAD⁺, whereas its 3 products are D-xylonolactone, NADH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is D-xylose:NAD⁺ 1-oxidoreductase. Other names in common use include NAD⁺-D-xylose dehydrogenase, D-xylose dehydrogenase, and (NAD⁺)-linked D-xylose dehydrogenase. This enzyme participates in pentose and glucuronate interconversions.