The Imperial Service Infantry Brigade was an infantry brigade of the British Indian Army that saw active service in the East African Campaign in the First World War.

The Imperial Service Infantry Brigade was formed in August 1914, mostly from Imperial Service Troops (forces raised by the princely states of the British Indian Empire), hence its name.

It was assigned to Indian Expeditionary Force B along with 27th (Bangalore) Brigade.

The Force sailed from Bombay (Mumbai) on 16 October with Tanga in German East Africa as the target for an attack.

After the failure of the Battle of Tanga (2–5 November), the Force disembarked at Mombasa and joined the defences of British East Africa.