腺苷酸环化酶（英语：Adenylate cyclase 或 adenylyl cyclase，EC4.6.1.1）是一种参与已知所有细胞的细胞调控的关键酶。

Adenylyl cyclase (EC4.6.1.1, also commonly known as adenyl cyclase and adenylate cyclase, abbreviated AC) is an enzyme with key regulatory roles in essentially all cells. It is the most polyphyletic known enzyme: six distinct classes have been described, all catalyzing the same reaction but representing unrelated gene families with no known sequence or structural homology. The best known class of adenylyl cyclases is class III or AC-III (Roman numerals are used for classes). AC-III occurs widely in eukaryotes and has important roles in many human tissues.