In enzymology, a ribitol 2-dehydrogenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are ribitol and oxidised nicotinamide adenine dinucleotide (NAD<sup>+</sup>). Its products are D-ribulose, reduced NADH, and a proton.
This enzyme participates in pentose and glucuronate interconversions.
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 ribitol:NAD<sup>+</sup> 2-oxidoreductase. Other names in common use include adonitol dehydrogenase, ribitol dehydrogenase A (wild type), ribitol dehydrogenase B (mutant enzyme with different properties), and ribitol dehydrogenase D (mutant enzyme with different properties).