In enzymology, glycolaldehyde dehydrogenase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are glycolaldehyde, oxidised nicotinamide adenine dinucleotide (NAD<sup>+</sup>), and water. Its products are glycolic acid, reduced NADH, and a proton.
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 glycolaldehyde:NAD+ oxidoreductase. This enzyme is also called glycol aldehyde dehydrogenase. This enzyme participates in glyoxylate and dicarboxylate metabolism.
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes , , and .