In Greek mythology, Andromeda was the daughter of Cepheus and Cassiopeia, king and queen of Ethiopia. Cassiopeia had bragged that she was more beautiful than the Nereids (water-nymphs), and so in revenge, Poseidon sent a flood and a sea monster to plague the land. Cepheus then consulted the oracle of Ammon, and was told that he had to sacrifice his daughter to the sea monster in order for the problem to end. His people forced him to comply with the oracle, and he chained Andromeda to a rock by the sea. She was rescued by Perseus who killed the monster and then married Andromeda. One of their children, Perses, became the ancestor of the kings of Persia.

Andromeda is Greek for "ruler of men". She is represented in the northern sky by the constellation Andromeda which contains the Andromeda Galaxy.

The name Andromeda may also refer to—

• a plant genus of the heath family.
• any one of several comic book characters.
• Gene Roddenberry's Andromeda, an American television series.
• In Space Battleship Yamato, an Earth-built dreadnought.
• a progressive metal band from Sweden.

See also Michael Crichton's novel The Andromeda Strain (1968).