Clearchus was an Athenian comic poet of the early 4th century BCE, likely active in the 380s. He is known only from fragments and testimonia. The Suda states he wrote seven plays, but modern scholarship attributes only two secure titles to him, and he is a distinct figure from other historical individuals named Clearchus.

The two comedies attributed to him are The Fisherman and The All-Seeing Ones, both surviving fragmentarily. The Suda lists other titles—Bacchae, Birth of Aphrodite, Birth of Pan, Heroes, Amphitryon—but these are considered doubtful or misattributed.

Clearchus is a minor figure within Middle Comedy. His fragments, often involving mythological parody and elements of fantasy, provide valuable glimpses into this transitional period between Old and New Comedy.