Pre-war, The Canadian Army consisted of the Permanent Forces and the Non Permanent Active Militia. On mobilisation at the outbreak of war, both became part of the Canadian Active Service Force. Three infantry divisions saw service during the campaign in North West Europe.

The 1 Canadian Infantry Division was activated on 1 September 1939. The 1 Canadian Infantry Brigade was raised in Ontario. It embarked for the United Kingdom on 17 December 1939, and arrived at Greenock on 25 December 1939. The 2 Canadian Infantry Brigade was raised in Western Canada. It embarked for the United Kingdom on 22 December 1939, and arrived at Greenock on 30 December. The 3 Canadian Infantry Brigade was raised in Quebec and the Maritimes. It was the first brigade to reach the United Kingdom on 17 December. On arrival in the U.K., it was concentrated in the Aldershot area. Following the evacuation of the bulk of the B.E.F. from Dunkirk, the 1 Canadian Infantry Brigade was sent to France in June 1940, but was withdrawn soon after landing. The division remained in the U.K. until sailing for Sicily, where it landed on 10 July 1943. It moved into Italy in September 1943. In March 1945, the division together with the rest of the I Canadian Corps transferred from Italy to North West Europe in order to bring all the Canadian formations together in one theatre of operations. The division disbanded in Holland on 15 September 1945.

The 2 Canadian Infantry Division was formed in Canada in February 1940 and transferred to the United Kingdom in December 1940. It formed the main core of the Force which took part in the Dieppe raid on 19 August 1942, suffering 3,600 casualties. It landed in Normandy on 7 July 1944 under the command of II Canadian Corps. The division entered the line near Caen on 18 July 1944, fighting in the battle for the River Orne, Bourguebus Ridge and Falaise. With the breakout, the division was tasked with capturing Dieppe to avenge the outcome of the Dieppe raid, which it achieved on 1 September 1944. It was allowed to remain there for a period of time to absorb 1,000 replacements and to facilitate a memorial parade. Later, the division was involved in the fighting to clear the River Scheldt in October and November 1944. It attacked north from Antwerp and advanced along the South Beveland peninsula, and into Germany. The division returned to Canada after the cessation of hostilities, being disbanded there in September 1945.

The 3 Canadian Infantry Division was formed in Canada on 5 September 1940, and transferred to the United Kingdom in July 1941. It landed on Juno Beach, Normandy, on 6 June 1944, under the command of I Corps. When the II Canadian Corps became active in Normandy on 13 July 1944, the division transferred to that Corps. The division fought battles for Caen, Carpiquet, Bourguebus Ridge, Falaise, le Laison, Boulogue-sur-Mer, the clearing of the River Scheldt, the Rhineland and the crossing of the River Rhine. The division remained in Germany in 1945 and 1946, as the Canadian element of the Canadian Army Occupation Force (C.A.O.F.). The C.A.O.F. was wound up on 15 May 1946, and the division disbanded in Germany on 20 June 1946.