In enzymology, an aryl-aldehyde dehydrogenase () is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are aromatic aldehyde, NAD<sup>+</sup>, and H<sub>2</sub>O, whereas its 3 products are aromatic acid, NADH, and H<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is aryl-aldehyde:NAD+ oxidoreductase. This enzyme participates in tyrosine metabolism and biphenyl degradation.