7th Black Watch saw action in France with the BEF. After the capture of the 51st Highland Division at St Valery in June 1940 it was decided to reconstitute it in the UK around a nucleus provided by the 9th Scottish Division. Less than thirty members of the old 1st Battalion were available, but it was rebuilt and joined by the 5th and 7th Battalions which had not yet gone overseas. 7th Black Watch arrived in North Africa in early 1943 as part of 51st Highland Division, taking part in the battle of El Alamein, followed by the pursuit across the North African desert through Mareth and Wadi Akarit ending with a triumphant entry into Tripoli. The 7th Battalion trained in amphibious landing vehicles in Algeria, using them in landing in Sicily in early July. It suffered severe casualties at Adrano at the end of July before German withdrawal to the north. The battalion, with the rest of the 51st Division, landed on the Italian mainland and six weeks later was moved to Britain to prepare for the D-Day operations in Normandy. The battalion suffered many casualties in Normandy and after the fall of Caen on 11th July 1944, was engaged in the push north to close the Falaise Gap.

St Valery, Le Havre, Dunkirk - the sites of previous defeats in 1940 - were all passed through with little German resistance. In February 1945 the battalion was part of the attack through the Reichswald, leading to continuous action under German artillery attack. It crossed the Rhine on 22nd March 1945 under severe shelling, the last major engagement before VE-Day.