Canadian Expeditionary Force Study Group

The battalion's battle honours are still carried by the 38th's perpetuating militia regiment, The Cameron Highlanders of Ottawa.

The battalion was officially authorized on 7 November 1914 as the "38th Battalion". Mobilized in Ottawa, Ontario, and immediately placed on active service, the battalion was recruited in Ottawa and parts of eastern Ontario. Popularly known throughout the war as the 38th "Ottawa" Battalion or the "Royal Ottawa's", the 38th drew its strength from several eastern Ontario regiments and "off the street" from civilian recruits. Its strength included, in particular, significant contributions from the 43rd Regiment "The Duke of Cornwall's Own Rifles" and the Governor General's Foot Guards upon formation.

Recruitment and training progressed in Ottawa and Barriefield (near Kingston) until August 1915. The battalion, with a total strength of 37 officers and 1038 non-commissioned members, sailed from Halifax aboard S.S. "Caledonian" on 8 August 1915 and arrived in Bermuda four days later. Under command of Lieutenant-Colonel Cameron Macpherson Edwards, the 38th served on garrison duty in Bermuda, replacing The Royal Canadian Regiment in that role. On 30 May 1916 the battalion sailed from Bermuda aboard S.S. "Grampian", arriving in Plymouth on 9 June.

The 38th sailed from Southampton aboard S.S. "Archangel" on 13 August 1916, arriving in Le Havre the following day. From then until 1919 the battalion served with the 12th Infantry Brigade of the 4th Canadian division and saw extensive service in France and Flanders.

In terms of individual honours and awards, the members of the 38th Battalion were awarded an astounding 299 decorations for bravery during the war. This list included two Victoria Crosses, nine Distinguished Service Orders, thirty-five Military Crosses, two Distinguished Flying Crosses (won by members seconded to the Royal Flying Corps), twenty-seven Distinguished Conduct Medals, 166 Military Medals, eight Meritorious Service Medals, thirty-eight Mentioned-in-Despatches, one Croix de Guerre avec Palme (French), one Croix de Chevalier Legion d'Honneur (French), one Medaille d'Honneur avec Glaives en Vermeil (French), two Medailles d'Honneur avec Glaives en Argent (French), four Croix de Guerre (Belgian), and three Crosses of St. George (4th Class) (Russian).

Major Thain Wendell MacDowell was awarded the Victoria Cross for his actions during the Battle of Vimy Ridge in April 1917 when he captured seventy-seven Germans in a dugout during the attack. Private Claude Joseph Patrick Nunney was awarded his Victoria Cross posthumously for his efforts on September 1 and 2, 1918, during the Battle of Drocourt-Quéant where he provided support fire, ammunition, and encouragement in several locations during the battle.

On 5 May 1919 the battalion sailed from Le Havre aboard S.S. "St. George", arriving in Southampton the next day. The 38th sailed from Southampton for Canada aboard S.S. "Olympic" on 6 June 1919, arrived in Halifax on 13 June, and was demobilized in Ottawa on 15 and 16 June. Nearly 4,000 officers, non-commissioned officers, and men passed through its ranks between its arrival in France in August 1916 and the armistice in November 1918. The battalion suffered more than 2,700 casualties (almost 800 killed in action, died of wounds, or died of disease, and nearly 2,000 wounded) during the fighting. It was officially disbanded on 30 August 1920.