The 37th Infantry Brigade was reformed on 7 October 1939 as a 2nd Line Territorial Army infantry brigade as a duplicate of 133rd Infantry Brigade. The 37th Infantry Brigade was with the 12th (Eastern) Infantry Division when they were sent in 1940 to France to join the British Expeditionary Force. The division suffered very heavy casualties during the Battle of France and was disbanded in July 1940 after having been evacuated to England from Dunkirk. In November 1941 the brigade joined the 3rd Infantry Division and was redesignated the 7th Infantry Brigade.