Mesopotamian sky god and a member of the triad of deities completed by Enlil and Ea (Enki). Like most sky gods, Anu, although theoretically the highest god, played only a small role in the mythology, hymns, and cults of Mesopotamia. He was the father not only of all the gods but also of evil spirits and demons, most prominently the demoness Lamashtu, who preyed on infants. Anu was also the god of kings and of the yearly calendar. He was typically depicted in a headdress with horns, a sign of strength.

His Sumerian counterpart, An, dates from the oldest Sumerian period, at least 3000 BC. Originally he seems to have been envisaged as a great bull, a form later disassociated from the god as a separate mythological entity, the Bull of Heaven, which was owned by An. His holy city was Uruk (Erech) (Erech), in the southern herding region, and the bovine imagery suggests that he belonged originally to the herders' pantheon. In Akkadian myth Anu was assigned a consort, Antum (Antu), but she seems often to have been confused with Ishtar (Inanna), the celebrated goddess of love.