In enzymology, a progesterone 11alpha-monooxygenase (EC 1.14.99.14) is an enzyme that catalyzes the chemical reaction

progesterone + AH₂ + O₂ 11alpha-hydroxyprogesterone + A + H₂O

The 3 substrates of this enzyme are progesterone, AH2, and O₂, whereas its 3 products are 11alpha-hydroxyprogesterone, A, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derive from O miscellaneous. The systematic name of this enzyme class is progesterone,hydrogen-donor:oxygen oxidoreductase (11alpha-hydroxylating). This enzyme is also called progesterone 11alpha-hydroxylase. This enzyme participates in c21-steroid hormone metabolism.

• Shibahara M, Moody JA, Smith LL (1970). "Microbial hydroxylations. V. 11-alpha-hydroxylation of progesterone by cell-free preparations of Aspergillus ochraceus". Biochim. Biophys. Acta. 202 (1): 172–9. doi:10.1016/0005-2760(70)90228-6. PMID 5417182.