A (−)-menthol dehydrogenase (EC 1.1.1.207) is an enzyme that catalyzes the chemical reaction

(−)-menthol + NADP⁺ ${\displaystyle \rightleftharpoons }$ (−)-menthone + NADPH + H⁺,

i.e., catalyses the breakdown of menthol. Thus, the two substrates of this enzyme are (−)-menthol and NADP⁺, whereas its 3 products are (−)-menthone, NADPH, 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 (−)-menthol:NADP⁺ oxidoreductase. This enzyme is also called monoterpenoid dehydrogenase. This enzyme participates in monoterpenoid biosynthesis.

• Kjonaas R, Martinkus-Taylor C, Croteau R (May 1982). "Metabolism of Monoterpenes: Conversion of l-Menthone to l-Menthol and d-Neomenthol by Stereospecific Dehydrogenases from Peppermint (Mentha piperita) Leaves". Plant Physiology. 69 (5): 1013–7. doi:10.1104/pp.69.5.1013. JSTOR 4267341. PMC 426349. PMID 16662335.