[16][1] Commanded by Archibald Ritchie, the 1st Battalion, which had been serving in India, landed at Marseilles as part of the Dehra Dun Brigade in the Meerut Division in October 1914 for service on the Western Front.

[17] The 2nd Battalion, which had been stationed at Shorncliffe Camp, landed at Boulogne-sur-Mer as part of the 10th Brigade in the 4th Division in August 1914.

[17] The 8th (Service) Battalion landed at Boulogne-sur-Mer as part of the 44th Brigade in the 15th (Scottish) Division in July 1915.

[17] The 1st Battalion returned from Egypt in 1919,[20] and in 1921 was deployed to Cowdenbeath and to Bridge of Allan to maintain order during strike action by the miners.

[23] Meanwhile, the 2nd Battalion went to India in 1918 and saw action on the North-West Frontier in 1930–31 before moving to Palestine in 1932 and returning to Britain in 1934.

[24] The 1st Battalion, which was stationed in Shanghai when war broke out, was deployed to Malaya in November 1940, and then to India.

[25] The 4th Battalion also went to France as part of the 152nd Brigade in the 51st Highland Infantry Division with the BEF in January 1940 and was captured at Saint-Valery-en-Caux in June 1940.

[26] After home service with the 9th (Highland) Infantry Division,[27] in 1940 the 5th Battalion joined the reconstituted 152nd Brigade, 51st Highland Division,[28] and served in the Middle East, in the Allied invasion of Sicily in July 1943, in the Allied invasion of Italy in September 1943 and then in North-West Europe.

[31] The 8th and 9th battalions were raised early in the war, and served in a home defence and reserve role.

[32] After the end of war, the 1st battalion served in Java before moving to Malaya where, from 1948 until 1951, it took part in internal security operations during the Malayan Emergency.

[34] Post-war, the regiment had one Territorial Army (TA) unit – the 11th battalion, Seaforth Highlanders.