In enzymology, xanthoxin dehydrogenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are xanthoxin and oxidised nicotinamide adenine dinucleotide (NAD<sup>+</sup>). Its products are abscisic aldehyde, reduced NADH, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD<sup>+</sup> or NADP<sup>+</sup> as acceptor. The systematic name of this enzyme class is xanthoxin:NAD<sup>+</sup> oxidoreductase. Other names in common use include xanthoxin oxidase, and ABA2. This enzyme participates in carotenoid biosynthesis.