乙酰辅酶A羧化酶（英语：Acetyl-CoA carboxylase）是一种生物素依赖的酵素，专门催化生物体内由乙酰辅酶A转变成丙二酰辅酶A的化学反应。

这种酵素可分为3个不同区域，分别是生物素载体蛋白（biotin carrier protein）、生物素羧化酶（biotin carboxylase）以及转羧酶（transcarboxylase）。对细菌来说，这3个区域分别是3个次单位；对动物来说则相连在同一多肽上；而植物细胞则同时拥有两种。

乙酰辅酶A在此酵素的催化之下，会经过两个步骤的反应，首先生物素载体蛋白上的生物素臂，会经由生物素羧化酶的催化，并消耗ATP，而与二氧化碳（HCO₃，溶于水后的状态）结合；接着二氧化碳又在转羧酶催化下与乙酰辅酶A，形成丙二酰辅酶A，并脱离乙酰辅酶A羧化酶。

Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-CoA through its two catalytic activities, biotin carboxylase (BC) and carboxyltransferase (CT). ACC is a multi-subunit enzyme in most prokaryotes and in the chloroplasts of most plants and algae, whereas it is a large, multi-domain enzyme in the endoplasmic reticulum of most eukaryotes. The most important function of ACC is to provide the malonyl-CoA substrate for the biosynthesis of fatty acids. The activity of ACC can be controlled at the transcriptional level as well as by small molecule modulators and covalent modification. The human genome contains the genes for two different ACCs — ACACA and ACACB.