General · EdgepediaSeptember 17, 20269 min read

Treaty of Lausanne

The Treaty of Lausanne was a peace treaty signed at Lausanne, Switzerland, on 24 July 1923 between Turkey and the British Empire, France, Italy, Japan, Greece, Romania, and the Serb-Croat-Slovene State, formally ending the state of war that had existed in the East since 1914¹. The agreement replaced the August 1920 Treaty of Sèvres, which had formally concluded World War I between the Allies and the Ottoman Empire but was never recognized by the Turkish nationalist movement². Lausanne was the last of the post-World War One peace settlements, and, together with the deposition of the Ottoman Sultan announced on 1 November 1922, it brought to a close the "Eastern Question," the shorthand used in European chancelleries for the dilemmas posed by the decline of the Ottoman Empire².

Key fact	Detail
Signed	24 July 1923 at Lausanne, Switzerland; registered with the League of Nations on 5 September 1924¹
Parties	British Empire, France, Italy, Japan, Greece, Romania, Serb-Croat-Slovene State, and Turkey¹
Replaced	Treaty of Sèvres of August 1920, concluded with the Ottoman government, with the Ankara "Government of the Grand National Assembly" signing instead²^•²¹
Population exchange	Compulsory exchange of Greek Orthodox residents of Turkey and Muslim residents of Greece from 1 May 1923, with exemptions for Constantinople and Western Thrace³
Scale of transfer	About 1.5 million Greeks left Turkey for Greece and about half a million Turks left Greece for Turkey⁴
Minority clauses	Protection guaranteed to non-Muslim minorities in Turkey and, reciprocally, to the Muslim minority in Greece⁵
Capitulations	Complete abolition of the Capitulations, the extraterritorial privileges formerly enjoyed by foreigners in Turkey⁵
Straits	A separate Lausanne Convention demilitarized the Straits; it was replaced by the Montreux Convention of 20 July 1936⁶

From Sèvres to Lausanne

Under the Treaty of Sèvres the Allies had dealt with the Ottoman government in Constantinople. Lausanne, by contrast, was concluded with the Ankara "Government of the Grand National Assembly," the precursor of the Turkish Republic. By treating with the Ankara government, the Allies acknowledged the assembly's formal abolition of the Ottoman Empire, announced on 1 November 1922, three weeks before the opening of the conference². The Kemalist insurgency had in two years turned the dictated peace of 1920 into victory, enabling Turkey to claim its place as the first sovereign state in the Middle East⁷.

Following the Mudanya Armistice that ended the war between Greece and the emerging Turkish state, the Great Powers summoned the representatives of both sides to negotiations at Lausanne. Sources give the opening date as 20 November 1922⁸ or 22 November 1922⁹. The conference ran, with an interruption, until the treaty was concluded on 24 July 1923⁸. Ankara's chief negotiator was İsmet İnönü, the future successor to Mustafa Kemal (Atatürk); the British representative was Lord Curzon¹⁰. Unlike the other postwar settlements, Lausanne treated an ex-enemy state as an equal at the negotiating table¹¹.

Territorial and political settlement

The treaty's political clauses fixed Turkey's European frontier with Bulgaria and Greece along the line of the Maritza and Arda rivers, and its southern frontier with Syria by reference to the Franco-Turkish Agreement of 20 October 1921⁵. Turkey recognized the British annexation of Cyprus proclaimed on 5 November 1914, renounced all rights over Egypt and Sudan effective from 5 November 1914, and ceded to Italy the Dodecanese islands then under Italian occupation, including Rhodes and Cos⁵. Greece's sovereignty over the eastern Aegean islands of Lemnos, Samothrace, Mytilene, Chios, Samos, and Nikaria was confirmed, while islands lying less than three miles from the Asiatic coast remained under Turkish sovereignty⁵.

The Mosul question was left open. Article 3 provided that the frontier between Turkey and Iraq would be settled by friendly arrangement between Turkey and Great Britain within nine months, failing which the dispute would go to the Council of the League of Nations⁵. At the conference itself, Lord Curzon stated on 23 January 1923 that the southern frontier of Turkish territory in Asia remained to be determined, and the dispute was referred to the League's enquiry and decision¹². Turkey ultimately renounced all rights and titles over the territory of Iraq under the treaty signed at Angora with Britain and the King of Iraq on 5 June 1926¹³.

Sovereignty and finance. The treaty abolished the Capitulations in Turkey in every respect, ending the regime of extraterritorial privileges⁵. It also settled the division of the Ottoman debt, a question Ankara's negotiators weighed heavily; in March 1923 İsmet likened the Allies' refusal to make concessions on the debt to an open invitation to resume war¹⁰. A separate Convention regarding the regime of the Straits, signed the same day, demilitarized the Dardanelles, the Sea of Marmara, and the Bosphorus and placed them under an international Commission; this regime lasted until the Montreux Convention of 20 July 1936 restored Turkish control⁶.

The United States did not sign the multilateral treaty. In the conference's second phase the American Minister to Switzerland, Joseph C. Grew, negotiated with the Turkish delegation led by İmet Pasha on a fully reciprocal basis, producing separate American-Turkish treaties concluded on 6 August 1923¹⁴.

The population exchange

Alongside the peace treaty, the Convention Concerning the Exchange of Greek and Turkish Populations was signed at Lausanne on 30 January 1923 by the Greek and Turkish delegates³. Under Article 1, a mandatory population swap was to begin on 1 May 1923, covering Turkish citizens of the Greek Orthodox faith living in Turkey and Greek citizens of the Muslim faith living in Greece, with neither group permitted to go back to their country of residence without approval from the respective government³. In accordance with the Turkish view of minorities, the sole basis of the exchange was religion¹⁵.

Article 2 exempted the Greek inhabitants of Constantinople and the Muslim inhabitants of Western Thrace³, and the treaty separately excluded the inhabitants of the islands of Imbros and Tenedos from any exchange agreement⁵. American intervention during the conference helped ensure the exemption of Constantinople from the transfer¹⁶.

This was the first compulsory exchange of populations bilaterally negotiated under Great Power auspices and agreed at a diplomatic table in pursuit of peace⁹. In its outcome, about a million and a half Greeks left Turkey for Greece and about half a million Turks left Greece for Turkey⁴. The convention came into effect on 6 August 1924, after Greece and Turkey ratified the Peace Treaty¹². A Mixed Commission oversaw application, including the liquidation of the property of those exchanged³.

Minority protection

Section III of the treaty (Articles 37 through 45) guaranteed non-Muslim minorities in Turkey full protection of life and liberty, equal civil and political rights, freedom of religion, the free use of any language, and the right to maintain their own schools, charities, and religious institutions, with these provisions placed under the guarantee of the League of Nations⁵. Article 45 extended the same rights to the Muslim minority in Greece⁵.

In practice the regime was narrower than its text. Turkey has traditionally applied the Lausanne rights only to three so-called non-Muslim groups, Greeks, Armenians, and Jews, and recognizes them as religious rather than ethnic minorities; groups such as the Kurds, Alevis, Laz, Circassians, and Roma have not received formal recognition as protected communities under the treaty¹⁷. Scholarly assessments a century on describe the minority provisions as having fallen short of their original purpose, shaped by an ideological legacy of the Ottoman millet system and by a strict interpretation of reciprocity between the two states¹⁸. The treaty's minority clauses also entrenched divisions formed in the Ottoman Empire during the violence of the preceding decade, and alarmed Turkish leaders who recalled how European powers had used the cause of Ottoman Christians to infringe on Ottoman sovereignty¹⁹.

Legacy

By fixing where Turkey's frontiers lay, ending the Capitulations, settling disputes over sovereignty and debt, placing the Straits under regulation, and creating a minority-protection regime for non-Muslims that operated under international oversight, Lausanne cemented the Republic of Turkey's emergence as the Ottoman Empire's sovereign successor²⁰. Its endorsement of compulsory demographic transfer institutionalized population exchange as a mechanism of state-building, and its legacy is assessed as ambivalent: a cornerstone of modern international law and, at the same time, an illustration of the limits of minority protection and international guarantees²⁰. It remains the only international convention still in force stemming from the post-World War One minority protection system¹⁸.

References

Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 25, 2026 · Edited: Sep 30, 2026; Oct 25, 2026