The Treaty of Lausanne was signed to settle part of the partition of the Ottoman Empire, establishing the boundaries of Greece, Bulgaria and Turkey.

The Treaty of Lausanne is a peace treaty negotiated during the Lausanne Conference of 1922–1923 and signed in the Palais de Rumine in Lausanne, Switzerland, on 24 July 1923. The treaty officially resolved the conflict that had initially arisen between the Ottoman Empire and the Allied French Republic, British Empire, Kingdom of Italy, Empire of Japan, Kingdom of Greece, Kingdom of Serbia, and the Kingdom of Romania since the outset of World War I. The original text of the treaty is in English and French. It emerged as a second attempt at peace after the failed and unratified Treaty of Sèvres, which had sought to partition Ottoman territories. The earlier treaty, signed in 1920, was later rejected by the Turkish National Movement which actively opposed its terms. As a result of Greek defeat in the Greco-Turkish War, Turkish forces recaptured İzmir, and the Armistice of Mudanya was signed in October 1922. This armistice provided for the exchange of Greek-Turkish populations and allowed unrestricted civilian, non-military passage through the Turkish Straits.

The partition of the Ottoman Empire was a geopolitical event that occurred after World War I and the occupation of Constantinople by British, French, and Italian troops in November 1918. The partitioning was planned in several agreements made by the Allied Powers early in the course of World War I, notably the Sykes–Picot Agreement, after the Ottoman Empire had joined Germany to form the Ottoman–German alliance. The huge conglomeration of territories and peoples that formerly comprised the Ottoman Empire was divided into several new states. The Ottoman Empire had been the leading Islamic state in geopolitical, cultural, and ideological terms. The partitioning of the Ottoman Empire after the war led to the domination of the Middle East by Western powers such as Britain and France, and saw the creation of the modern Arab world and the Republic of Turkey. Resistance to the influence of these powers came from the Turkish National Movement but did not become widespread in the other post-Ottoman states until the period of rapid decolonization after World War II.