The Gloucestershire Regiment, commonly referred to as the Glosters, was a line infantry regiment of the British Army from 1881 until 1994. It traced its origins to Colonel Gibson's Regiment of Foot, which was raised in 1694 and later became the 28th Regiment of Foot. The regiment was formed by the merger of the 28th Regiment with the 61st Regiment of Foot. It inherited the unique distinction in the British Army of wearing a badge on the back of its headdress as well as the front, a tradition that originated with the 28th Regiment after it fought in two ranks back to back at the Battle of Alexandria in 1801. At its formation the regiment comprised two regular, two militia and two volunteer battalions, and saw its first action during the Second Boer War.

The Territorial Force was a part-time volunteer component of the British Army, created in 1908 to augment British land forces without resorting to conscription. The new organisation consolidated the 19th-century Volunteer Force and yeomanry into a unified auxiliary, commanded by the War Office and administered by local county territorial associations. The Territorial Force was designed to reinforce the regular army in expeditionary operations abroad, but because of political opposition it was assigned to home defence. Members were liable for service anywhere in the UK and could not be compelled to serve overseas. In the first two months of the First World War, territorials volunteered for foreign service in significant numbers, allowing territorial units to be deployed abroad. They saw their first action on the Western Front during the initial German offensive of 1914, and the force filled the gap between the near destruction of the regular army that year and the arrival of the New Army in 1915. Territorial units were deployed to Gallipoli in 1915 and, following the failure of that campaign, provided the bulk of the British contribution to allied forces in the Sinai and Palestine Campaign. By the war's end, the Territorial Force had fielded twenty-three infantry divisions and two mounted divisions on foreign soil. It was demobilised after the war and reconstituted in 1921 as the Territorial Army.