The Royal Scots Fusiliers was a line infantry regiment of the British Army that existed from 1678 until 1959 when it was amalgamated with the Highland Light Infantry (City of Glasgow Regiment) to form the Royal Highland Fusiliers (Princess Margaret's Own Glasgow and Ayrshire Regiment) which was later itself merged with the Royal Scots Borderers, the Black Watch (Royal Highland Regiment), the Argyll and Sutherland Highlanders and the Highlanders (Seaforth, Gordons and Camerons) to form a new large regiment, the Royal Regiment of Scotland.

The 4/5th and 6th battalions both saw service in the European Campaign in 1944-1945 with the 6th also serving in France in 1940, assigned to 51st (Highland) Infantry Division and part of the BEF. The 4/5th Battalion was the TA 4th and 5th battalions merged and became part of 156th Infantry Brigade assigned to the 52nd (Lowland) Infantry Division. Lieutenant Colonel Thomas Corbett commanded the 6th Battalion during the Battle of France in June 1940.

The 6th Battalion was reassigned to the 46th Infantry Brigade part of 15th (Scottish) Infantry Division, the 2nd Line duplicate of the 52nd, and served with them during the Battle of Normandy.