In enzymology, a L-rhamnose 1-dehydrogenase (EC 1.1.1.173) is an enzyme that catalyzes the chemical reaction

L-rhamnofuranose + NAD⁺ ${\displaystyle \rightleftharpoons }$ L-rhamno-1,4-lactone + NADH + H⁺

Thus, the two substrates of this enzyme are L-rhamnofuranose and NAD⁺, whereas its 3 products are L-rhamno-1,4-lactone, 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 L-rhamnofuranose:NAD⁺ 1-oxidoreductase. This enzyme participates in fructose and mannose metabolism.