A. J. Crowley is a fictional demon in the novel Good Omens by Terry Pratchett and Neil Gaiman. Originally named Crawley, he was supposedly the serpent who tempted Adam and Eve with the Fruit of Knowledge.

He went on to become Hell's agent on Earth, under the guise of a stereotyped yuppie. He is fascinated by humanity's ability to do worse things to each other than the legions of Hell could imagine (largely because the legions of Hell have no imagination). The personal achievements he himself is most satisfied with include Welsh-language television, value-added tax, the M25 London Orbital Motorway and Manchester.

He has a strong friendship with his opposite number, the angel Aziraphale. The two often meet up to compare notes, much like Cold War agents who find they have more in common with their immediate opponents than their distant superiors.

The character's name is a reference to the occultist Aleister Crowley, which is played on in the book - although his initials are revealed in an early scene, it is not until he answers a phone call much later on that his first name is revealed to not be Aleister at all, but Anthony.