Amphitrite, in ancient Greek mythology, was a sea-goddess, and wife of Poseidon, identified with the Salacia the wife of Neptune in Roman mythology.

She was daughter of Nereus and Doris according to Hesiod's Theogony but of Oceanus and Tethys according to Apollodorus. But Apollodorus actually lists her also among the Nereids.

Amphitrite ("the third one who encircles (the sea)") was so entirely confined in her authority to the sea and the creatures in it, that she was never associated with her husband either for purposes of worship or in works of art, except when he was to be distinctly regarded as the god who controlled the sea.

Amphitrite was distinguishable from the other Nereids only by her queenly attributes. It was said that Poseidon saw her first dancing at Naxos among the other Nereids, and carried her off. But in another version of the myth, she then fled from him to the farthest ends of the sea, where the dolphin of Poseidon found her, and was rewarded by being placed among the stars.

Poseidon had one son by Amphitrite, Triton and a daughter, Rhode (if this Rhode was not actually fathered by Poseidon on Halia or was not the dauther of Asopus as others claim.) Apollodorus (3.15.4) also mentions a daughter of Poseidon and Amphitrite named Benthesikyme.

In works of art Amphitrite is represented either enthroned beside him, or driving with him in a chariot drawn by sea-horses or other fabulous creatures of the deep, and attended by Tritons and Nereids. She is dressed in queenly robes and has nets in her hair. The pincers of a lobster are sometimes shown attached to her temple.

In poetry, her name is often used for the sea.