Aeneas of Stymphalus was a Greek military writer from the city of Stymphalus in Arcadia, active in the mid-4th century BCE. No details of his personal life survive, but his work indicates practical military experience, suggesting he served as a soldier or commander.

His only known work is the Poliorketika, or On the Defence of Fortified Positions, a treatise on siegecraft and military strategy that survives, though possibly incomplete. Aeneas is the earliest Greek military writer whose work survives to any substantial extent.

His treatise provides crucial, practical evidence for 4th-century BCE warfare, fortification, and siege tactics prior to the Hellenistic period. It covers sentry duties, cryptography, signaling, and defense against siege engines, serving as a key primary source for the realities of Greek warfare beyond pitched battle.