This is a list of Royal Northumberland Fusiliers battalions in World War II. At the outbreak of the Second World War in September 1939 the Royal Northumberland Fusiliers, a fusilier infantry regiment of the British Army, consisted of seven battalions. A further three were raised during the war. Prior to the war, the regiment was one of a number that been selected to transition from an infantry role to a support role and be equipped with the Vickers machine gun. While most battalions served as divisional machine gun or support battalions, several undertook different roles: motorcycle, searchlight, tank, reconnaissance, regular infantry, and deception units. The regiment saw action with the British Expeditionary Force (BEF) during the Battle of France and Dunkirk, defended the United Kingdom, fought in the North African Campaign, took part in the Battle of Singapore, fought in the Italian Campaign, and operated with the 21st Army Group in the North-West Europe Campaign of 1944–45, operating on the Western Front.