The Territorial Force War Medal was a campaign medal awarded to members of the British Territorial Force and Territorial Force Nursing Services who served overseas in World War I; it is the rarest of the five British Great War medals.

The medal was established in April 1920 for award to members of the Territorial Force and Territorial Force Nursing Services who volunteered for service overseas on or before 30 September 1914, and served overseas. They had to have been serving with the force on 4 August 1914 or have completed four years service with the force before 4 August 1914 and rejoined the force on or before 30 September 1914.