There were two characters named Epeius (/ᵻˈpaɪ.əs/; Ancient Greek: Ἐπειός) in Greek mythology.
- A Greek soldier during the Trojan War. He was the son of Panopeus and had the reputation for being a coward. In the Iliad he participated in the boxing match at the funeral games for Patroclus against Euryalus and won. Later during the funeral games for Achilleus he fought Acamas the son of Theseus to a stalemate. He built the Trojan Horse, commissioned by Odysseus because Athena had told him in a dream she would be with him to help build it. The horse was hollow and was large enough to hold 30 Greek soldiers equipped with all their armor but Epeius made the Trojan horse so tall that it could not fit through any of the gates of Troy. The trap door of the horse was fastened with a special catch that only Epeius could undo. After constructing the massive horse, he chose the other 29 soldiers that would accompany him inside the horse. He also founded Pisa and Metapontum.
- Son of King Endymion of Elis. He ran a race at Olympia, against his brothers Aetolus and Paeon, winning his father's kingdom. He was married to Anaxiroe, daughter of Coronus, and had one daughter, Hyrmine. Oenomaus was his contemporary.
The alternative spelling of "Epeus" may also be encountered.