The 18th Indian Division was formed during World War I in 1917 from units of the British Indian Army, for service in Mesopotamia and Persia, in what was called the Mesopotamia Campaign. The Division was attached to the Tigris Corps and was involved in the Actions at the Fat-ha Gorge and on the Little Zab between the 23–26 October 1918 and the Battle of Sharqat between 28–30 October 1918. At the end of the war the division would remain in Iraq as part of the Iraq Occupation Force, until it was disbanded in 1920.