The 12th Indian Division was formed in March 1915 from units of the British Indian Army. It formed part of the Tigris Corps, for service during the Mesopotamia Campaign of World War I. The Division arrived in Mesopotamia in April 1915 and remained there until it was broken up in March 1916.The Division's brigades remained in Mesopotamia as independent formations until forming part of the 15th Indian Division in May 1916.During its short existence it fought in a number of actions including the Battle of Shaiba between April 12–14, 1915, the between May 14–16, 1915, the between July 5, 13-14, 24 1915, where 400 British and Indian soldiers were killed in the battle and up to 2,000 Turkish Soldiers. The Occupation of Nasiriya and the affair at , January 14, 1916.