In enzymology, a 3-oxoacyl-[acyl-carrier-protein] reductase (EC 1.1.1.100) is an enzyme that catalyzes the chemical reaction

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group as hydride donor with NAD⁺ or NADP⁺ as hydride acceptor. The systematic name of this enzyme class is (3R)-3-hydroxyacyl-[acyl-carrier-protein]:NADP⁺ oxidoreductase. Other names in common use include beta-ketoacyl-[acyl-carrier protein](ACP) reductase, beta-ketoacyl acyl carrier protein (ACP) reductase, beta-ketoacyl reductase, beta-ketoacyl thioester reductase, beta-ketoacyl-ACP reductase, beta-ketoacyl-acyl carrier protein reductase, 3-ketoacyl acyl carrier protein reductase, 3-ketoacyl ACP reductase, NADPH-specific 3-oxoacyl-[acylcarrier protein]reductase, and 3-oxoacyl-[ACP]reductase. This enzyme participates in fatty acid biosynthesis and polyunsaturated fatty acid biosynthesis.

As of late 2007, 21 structures have been solved for this class of enzymes, with PDB accession codes 1I01, 1O5I, 1Q7B, 1Q7C, 1ULS, 1UZL, 1UZM, 1UZN, 2A4K, 2B4Q, 2C07, 2FR0, 2FR1, 2NM0, 2NTN, 2P68, 2PFF, 2PH3, 2PNF, 2UVD, and 2Z5L.