The Battle of Gaugamela (/ˌɡɔːɡəˈmiːlə/ GAW-gə-MEE-lə; Ancient Greek: Γαυγάμηλα, romanized: Gaugámēla, lit. 'the Camel's House'), also called the Battle of Arbela (Ἄρβηλα, Árbēla), took place in 331 BC between the forces of the Army of Macedon under Alexander the Great and the Persian Army under King Darius III. It was the second and final battle between the two kings, and is considered to be the final blow to the Achaemenid Empire, resulting in its complete conquest by Alexander.

The fighting took place in Gaugamela, a village on the banks of the river Bumodus, north of Arbela (modern-day Erbil, in Iraqi Kurdistan). Despite being heavily outnumbered, the Army of Macedon emerged victorious due to the employment of superior tactics and the clever usage of light infantry forces. It was a decisive victory for the League of Corinth, and it led to the fall of the Achaemenid Empire and of Darius III.