Philoxenus of Cythera was a Greek poet active in the late 5th and early 4th centuries BCE. He was born on the island of Cythera and is best known as a composer of dithyrambs, a type of choral song for Dionysus. He worked as a professional poet, competing in musical contests and spending time at the court of Dionysius I, the tyrant of Syracuse in Sicily. According to later stories, he was imprisoned by the tyrant, possibly for criticizing his poetry, before leaving for mainland Greece.

His most famous work is the dithyramb Cyclops or Galatea, which survives only in fragments. The poem presented the myth of the Cyclops Polyphemus falling in love with the sea-nymph Galatea as a humorous burlesque. According to modern scholars, this marked a significant innovation, moving the traditionally solemn dithyramb toward a more theatrical, narrative, and entertaining style. He is often associated with the "New Music" movement, a group of poets known for their creative experiments.

Philoxenus was a well-known and influential figure in antiquity. His work was referenced by the comic playwright Aristophanes and discussed by the philosopher Aristotle. His reputation endures as that of a skilled poet who helped expand the expressive range of ancient Greek choral poetry.