The Battle of Issus (or more commonly The Battle at Issus) occurs in southern Anatolia, in November 333 BCE.

The invading troops led by the young Alexander of Macedon, outnumbered more than 2:1, defeat the army personally led by Darius III of Achaemenid Persia in the second great battle for primacy in Asia.

After Alexander's forces successfully force a crossing of the Hellespont (the Dardanelles) and defeat the Persian satraps in a prior encounter, the Battle of the Granicus, Darius takes personal charge of his army, gathers a large army from the depths of the empire, and maneuvers to cut the Greek line of supply, requiring Alexander to countermarch his forces, setting the stage for the battle near the mouth of the Pinarus River and south of the village of Issus.