In classical mythology, Epopeus (; 'all-seer', derived from epopao "to look out", "observe", from epi "over" and ops "eye"), was a king of Lesbos (the large island in the Aegean Sea opposite the coast of Asia Minor) who committed incest with his daughter Nyctimene.
The name Nycteus signifies "of the night", as does Nyctimene in the following variant: according to accounts by the Roman Gaius Julius Hyginus and in Ovid's Metamorphoses (ii.590), an Epopeus was a king of Lesbos. He had sexual intercourse with his henceforth nocturnal daughter Nyctimene, whom Minerva in pity transformed into an owl, the bird that shuns the daylight.