The Greco–Turkish War of 1919–1922, also called the War in Asia Minor, or the Greek campaign of the Turkish War of Independence, is a series of military events occurring during the partitioning of the Ottoman Empire after the First World War between May 1919 and October 1922.

The war is fought between Greece and Turkish revolutionaries of the Turkish National Movement that are later to establish the Republic of Turkey.The Greek campaign is launched because the western Allies, particularly British Prime Minister David Lloyd George, have promised Greece territorial gains at the expense of the Ottoman Empire.

It ends with Greece giving up all territory gained during the war, returning to its pre-war borders, and engaging in a population exchange with the newly established state of Turkey under provisions in the Treaty of Lausanne.The collective failure of the military campaigns of Greece, and of the Turkish-Armenian and Franco-Turkish Wars against the Turkish revolutionaries, has forced the Allies to abandon the Treaty of Sèvres and negotiate at Lausanne a new treaty, recognizing the independence of the Turkish Republic and its sovereignty over Eastern Thrace and Anatolia.