Irish communities in Canada raised several Regiments during the First World War, which were used to provide replacement drafts for the Canadian Expeditionary Force (CEF) battalions in Europe.

The Canadian Irish Rangers was raised during November 1914 and sent a detachment to join the 60th Infantry Bttn in June 1915. After being redesignated as 199th Bttn BEF, it went on a recruitment tour of Ireland at the end of 1916/early 1917, before the battalion was amalgamated with the 22nd and 23rd (Reserve) Bttns and disbanded in 1917.

The Canadian Irish Fusiliers was formed before the war in Vancouver. After the outbreak of war, it sent replacement drafts to the CEF's 121st Bttn (New Westminster). The Regiment was drafted into the 7th Canadian Infantry Bttn (British Columbia) and served in France and Flanders from early 1915 onwards.

The Irish Regiment of Canada was formed in Toronto in late 1915 and was designated 110th Irish Regiment. They raised a number of battalons, including the 110th Canadian Overseas Battalion and 208th Irish Battalion, which served on the Western Front in France and Belgium.