The Kingdom of Iraq under British Administration or Mandatory Iraq (Arabic: الانتداب البريطاني على العراق‎) was created under the League of Nations Class A mandate under Article 22 and entrusted to Britain, when the Ottoman Empire was divided in August 1920 by the Treaty of Sèvres, following World War I. This award was prepared on April 25, 1920, at the San Remo conference in Italy. France controlled the Mandates of Syria and Lebanon.

Faisal ibn Husayn, who had been proclaimed King of Syria by a Syrian National Congress in Damascus in March 1920, was ejected by the French in July of the same year. Faisal was then granted by the British the territory of Iraq, to rule it as a kingdom, with the British RAF retaining certain military control, though de facto, the territory remained under British Mandate until 1932.

The civil government of postwar Iraq was headed originally by the High Commissioner, Sir Percy Cox, and his deputy, Colonel Arnold Wilson. British reprisals after the murder of a British officer in Najaf failed to restore order. British administration had yet to be established in the mountains of north Iraq. The most striking problem facing the British was the growing anger of the nationalists, who felt betrayed at being accorded mandate status.

British Mandate may refer to: