In enzymology, an acyl-CoA oxidase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are acyl-CoA and O<sub>2</sub>, whereas its two products are trans-2,3-dehydroacyl-CoA and H<sub>2</sub>O<sub>2</sub>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with oxygen as acceptor. The systematic name of this enzyme class is acyl-CoA:oxygen 2-oxidoreductase. Other names in common use include fatty acyl-CoA oxidase, acyl coenzyme A oxidase, and fatty acyl-coenzyme A oxidase. This enzyme participates in 3 metabolic pathways: fatty acid metabolism, polyunsaturated fatty acid biosynthesis, and ppar signaling pathway. It employs one cofactor, FAD.
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .