Elpenor (Ancient Greek: Ἐλπήνωρ) was the youngest comrade of Odysseus in Greek mythology. While on the island of Circe, he became drunk and decided to spend the night on the roof. In the morning he slipped on the ladder, fell, and broke his neck, dying quickly.

Elpenor was not especially notable for his intelligence or strength, but he survived the Trojan War, and appears in the Odyssey. He is the youngest man to survive the Laestrygonians. While Odysseus was staying on Aeaea, Circe's island, Elpenor became drunk and climbed onto the roof of Circe's palace to sleep. The next morning, waking upon hearing his comrades making preparations to travel to Hades, he forgot he was on the roof and fell, breaking his neck and dying. Odysseus and his men apparently noticed his absence, but they were too busy to look for him. When Odysseus arrived in Hades, Elpenor was the first shade to meet him, and pleaded with him to return to Aeaea and give his body a proper cremation and burial. After finishing his task in the underworld, Odysseus returned to Aeaea and cremated Elpenor's body, then buried his ashes with his armour and marked the grave with an oar of his ship.

Classicist Michael C. J. Putnam, discussing the Aeneid, suggests that perhaps Elpenor in earlier versions of the Odyssey may have been the pilot for Odysseus.

The story of Elpenor was the model for the story of Palinurus in Virgil's Aeneid. In the Aeneid, Palinurus, one of Aeneas' men, falls overboard and ends up swimming to an island nearby. He is killed on the island by the natives that live there. Later on in the story, Aeneas travels to the underworld where he sees Palinurus. There, Palinurus pleads with Aeneas to give him a proper burial.

Biblical scholar Dennis MacDonald compares the story of Elpenor to Plato's Myth of Er, and also suggests that Luke may have adapted Elpenor's tale for the story of Eutychus in the New Testament.