It served in the Mesopotamian Campaign on the Euphrates Front throughout its existence.

The 12th Indian Brigade was formed at Nasirabad in 5th (Mhow) Division in January 1915.

[1] It was transferred to Mesopotamia and joined the 12th Indian Division on formation at the end of March.

The brigade took part in the action of As Sahilan (11 September 1916), the Capture of Ramadi (28 and 29 September 1917), the Occupation of Hīt (9 March 1918) and the action of Khan Baghdadi (26 and 27 March 1918).

[4] At the end of the war, the division was rapidly run down and it (along with the brigade) was disbanded in March 1919.