The British Mandate for Palestine, also known as the Mandate for Palestine or the Palestine Mandate, was a League of Nations mandate for the territory that had formerly constituted the Ottoman Empire sanjaks of Nablus, Acre, the Southern part of the Vilayet of Syria, the Southern portion of the Beirut Vilayet, and the Mutasarrifate of Jerusalem, prior to the Armistice of Mudros.

The draft of the Mandate for Palestine was formally confirmed by the Council of the League of Nations on 24 July 1922, supplemented via the 16 September 1922 Trans-Jordan memorandum and then came into effect on 29 September 1923, following the ratification of the Treaty of Lausanne, with the United Kingdom as the administering mandatory.

The document was based on the principles contained in Article 22 of the Covenant of the League of Nations and of the San Remo Resolution of 25 April 1920, which embodied decisions made after World War I at the San Remo conference, where the Supreme Council of the Principal Allied Powers was reconvened. The objective of the League of Nations Mandate system was to administer parts of the defunct Ottoman Empire, which had been in control of the Middle East since the 16th century, “until such time as they are able to stand alone”. The approximate northern border with the French Mandate was agreed upon in the Paulet–Newcombe Agreement of 23 December 1920.

Transjordan had been a no man’s land after the Battle of Maysalun in July 1920. During this period, the British chose to avoid any definite connection with Palestine until a March 1921 conference at which it was agreed that Abdullah bin Hussein would administer the territory under the auspices of the Palestine Mandate. The Trans-Jordan Memorandum provided the detail to support Article 25 of the Mandate, such that the Jewish National Home did not apply to the territory east of the Jordan River. It also established a separate “Administration of Trans-Jordan” for the application of the Mandate, under the general supervision of Great Britain. Transjordan became largely autonomous under British tutelage according to an agreement of February 20, 1928, and fully independent under a treaty with Britain of March 22, 1946.

On 29 November 1947, the United Nations Partition Plan for Palestine was passed, envisaging the creation of separate Jewish and Arab states operating under economic union with Jerusalem being transferred to UN trusteeship. Two weeks later, Arthur Creech Jones announced that the British Mandate would terminate on 15 May 1948. On the last day of the Mandate, the creation of the State of Israel was proclaimed, and the 1948 Arab–Israeli War began.