The Battle of Sakarya (Turkish: Sakarya Meydan Muharebesi), also known as the Battle of the Sangarios (Greek: Μάχη του Σαγγάριου), was an important engagement in the Greco-Turkish War (1919–1922), the western front of the Turkish War of Independence.
The battle went on for 21 days from August 23 to September 13, 1921, close to the banks of the Sakarya River in the immediate vicinity of Polatlı, which is today a district of the Ankara Province.
It is also known as the Officers' Battle (Turkish: Subaylar Savaşı) in Turkey because of the unusually high casualty rate (70–80%) among the officers.
The Battle of Sakarya is considered as the turning point of the Turkish War of Independence.