The Mandate for Syria and Lebanon (French: Mandat français pour la Syrie et le Liban; Arabic: الانتداب الفرنسي على سوريا ولبنان al-intidāb al-fransi 'ala suriya wa-lubnān) (1923−1946) was a League of Nations mandate founded after the First World War and the partitioning of the Ottoman Empire concerning Syria and Lebanon. The mandate system was supposed to differ from colonialism, with the governing country acting as a trustee until the inhabitants would be able to stand on their own. At that point, the mandate would terminate and an independent state would be born.
During the two years that followed the end of the war in 1918 – and in accordance with the Sykes-Picot Agreement signed by Britain and France during the war – the British held control of most of Ottoman Mesopotamia (modern Iraq) and the southern part of Ottoman Syria (Palestine and Transjordan), while the French controlled the rest of Ottoman Syria, Lebanon, Alexandretta (Hatay) and other portions of southeastern Turkey. In the early 1920s, British and French control of these territories became formalized by the League of Nations' mandate system, and on 29 September 1923 France was assigned the League of Nations mandate of Syria, which included the territory of present-day Lebanon and Alexandretta in addition to Syria proper.
The administration of the region under the French was carried out through a number of different governments and territories, including the Syrian Federation (1922–24), the State of Syria (1924–30) and the Syrian Republic (1930–1958), as well as smaller states: the State of Greater Lebanon, the Alawite State and Jabal Druze State. Hatay was annexed by Turkey in 1939. The French mandate lasted until 1943, when two independent countries emerged, Syria and Lebanon. French troops completely left Syria and Lebanon in 1946.
With the defeat of the Ottomans in Syria, British troops, under General Sir Edmund Allenby, entered Damascus in 1918 accompanied by troops of the Arab Revolt led by Faisal, son of Sharif Hussein of Mecca. Faisal established the first new postwar Arab government in Damascus in October 1918, and named Ali Rida Pasha ar-Rikabi a military governor.
The new Arab administration formed local governments in the major Syrian cities, and the pan-Arab flag was raised all over Syria. The Arabs hoped, with faith in earlier British promises, that the new Arab state would include all the Arab lands stretching from Aleppo in northern Syria to Aden in southern Yemen.
However, in accordance with the secret Sykes–Picot Agreement between Britain and France, General Allenby assigned to the Arab administration only the interior regions of Syria (the eastern zone). Palestine (the southern zone) was reserved for the British. On 8 October, French troops disembarked in Beirut and occupied the Lebanese coastal region south to Naqoura (the western zone), replacing British troops there. The French immediately dissolved the local Arab governments in the region.