In enzymology, orotate reductase (NADPH) () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are (S)-dihydroorotic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP<sup>+</sup>). Its products are orotic acid, reduced NADPH, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-dihydroorotate:NADP+ oxidoreductase. Other names in common use include orotate reductase, dihydroorotate dehydrogenase, dihydro-orotic dehydrogenase, L-5,6-dihydro-orotate:NAD+ oxidoreductase, and orotate reductase (NADPH). It has one cofactor, FAD.