Chaerephon (/ˈkɛrəfən, -ˌfɒn/; Greek: , Chairephōn; c. 470/460 – 403/399 BCE), of the Athenian deme Sphettus, was an Ancient Greek best remembered as a loyal friend and follower of Socrates. He is known only through brief descriptions by classical writers and was "an unusual man by all accounts", though a man of loyal democratic values.
Chaerephon is mentioned by three writers of his time, all of whom were probably well acquainted with him: Aristophanes, Xenophon, and Plato. Considered together, these sources suggest that Chaerephon was a well-known, alert, energetic, engaging individual, possibly with a distinctive physical appearance and probably a bit of a "character", who moved easily in the social and intellectual circles of the day.
Chaerephon appears in three of Aristophanes' comic plays: The Clouds, The Wasps, and The Birds. The Clouds, produced in 423 BCE, portrays Socrates and his assistant Chaerephon as a pair of charlatans operating a pseudo-scientific school in Athens. Chaerephon is represented in The Clouds as pale and malnourished, a "living corpse", and it is sometimes inferred that he must have been a thin, unhealthy looking fellow in real life. In The Wasps Chaerephon, or some visual caricature of him, has a brief, non-speaking role as an impartial witness. In The Birds he is nicknamed "the bat", possibly alluding to nocturnal habits, a bony appearance, or a sudden, excitable nature (as suggested in Plato's works, below).