The Battle of the Aous was fought in 274 BC between the invading Epirote army of Pyrrhus of Epirus and the army of Antigonus II Gonatas of Macedon near the Aous (or Aoös, Greek Αώος, modern Vjosa) river.
In 275 BC Pyrrhus retreated from Italy and returned to Epirus. He came with a large army but had little money left to pay them. Pyrrhus planned a campaign into Macedonia for the next year with 8,000 infantry and 500 cavalry to which he added Gallic mercenaries. The expedition originally planned as a limited raid turned into a full-scale invasion when Pyrrhus met with more success than he expected. Pyrrhus captured a number of Macedonian towns and over 2,000 Macedonian soldiers had switched sides and joined the Epirote ranks.