The 1923 population exchange between Greece and Turkey stemmed from the "Convention Concerning the Exchange of Greek and Turkish Populations" signed at Lausanne, Switzerland, on 30 January 1923, by the governments of Greece and Turkey. It involved at least 1.6 million people (1,221,489 Greek Orthodox from Asia Minor, Eastern Thrace, the Pontic Alps and the Caucasus, and 355,000–400,000 Muslims from Greece), most of whom were forcibly made refugees and de jure denaturalized from their homelands.
On 16 March 1922, Turkish Minister of Foreign Affairs Yusuf Kemal Tengrişenk stated that "[t]he Ankara Government was strongly in favour of a solution that would satisfy world opinion and ensure tranquillity in its own country", and that "[i]t was ready to accept the idea of an exchange of populations between the Greeks in Asia Minor and the Muslims in Greece". Eventually, the initial request for an exchange of population came from Eleftherios Venizelos in a letter he submitted to the League of Nations on 16 October 1922, following Greece's defeat in the Greco-Turkish War and two days after their accession of the Armistice of Mudanya. The request intended to normalize relations de jure, since the majority of surviving Greek inhabitants of Turkey had fled from recent genocidal massacres to Greece by that time already. Venizelos proposed a "compulsory exchange of Greek and Turkish populations", and asked Fridtjof Nansen to make the necessary arrangements. The new state of Turkey also envisioned the population exchange as a way to formalize and make permanent the flight of its native Greek Orthodox peoples while initiating a new exodus of a smaller number (400,000) of Muslims from Greece as a way to provide settlers for the newly depopulated Orthodox villages of Turkey. Norman M. Naimark claimed that this treaty was the last part of an ethnic cleansing campaign to create an ethnically pure homeland for the Turks. Historian Dinah Shelton similarly wrote that "the Lausanne Treaty of 1923 completed the process of the forcible transfer of the Greeks".