Phaedo of Elis was a Greek philosopher and the youngest student of Socrates. Born in the last years of the 5th century BCE, Phaedo was a native of Elis and of high birth. He was taken prisoner in his youth, and passed into the hands of an Athenian slave dealer; being of considerable personal beauty, he was forced into prostitution. He subsequently came into contact with Socrates at Athens, who warmly received him and had him freed. He was present at the death of Socrates, and Plato named one of his most famous dialogues Phaedo.

After the death of Socrates he returned to Elis, and founded the Elean School of philosophy. Almost nothing is known of his doctrines, none of his writings are preserved.