Mandatory Palestine is a geopolitical entity established between 1920 and 1948 in the region of Palestine under the terms of the Mandate for Palestine.

During the First World War (1914–18), an Arab uprising and the British Empire's Egyptian Expeditionary Force under General Edmund Allenby had driven the Turks out of the Levant during the Sinai and Palestine Campaign.

The United Kingdom had agreed in the McMahon–Hussein Correspondence that it would honor Arab independence if they revolted against the Ottomans, but the two sides had different interpretations of this agreement, and in the end, the UK and France divided up the area under the Sykes–Picot Agreement—an act of betrayal in the eyes of the Arabs.

Further complicating the issue was the Balfour Declaration of 1917, promising British support for a Jewish "national home" in Palestine.

At the war's end the British and French has set up a joint "Occupied Enemy Territory Administration" in what had been Ottoman Syria.

The British achieve legitimacy for their continued control by obtaining a mandate from the League of Nations in June 1922.

The formal objective of the League of Nations mandate system is to administer parts of the defunct Ottoman Empire, which had been in control of the Middle East since the sixteenth century, "until such time as they are able to stand alone."

During the Mandate, Palestine sees the rise of two nationalist movements, the Jews and the Palestinian Arabs.

Competing interests of the two populations lead to the 1936–39 Arab revolt in Palestine and the 1944 -1948 Jewish insurgency in Mandatory Palestine.

After the failure of the United Nations Partition Plan for Palestine, the 1947–1949 Palestine war ends with Mandatory Palestine divided between Israel, the Jordanian annexation of the West Bank and the Egyptian All-Palestine Protectorate in the Gaza Strip.