The service of the 1st Battalion Royal Irish Rifles in World War I saw the battalion serving on the Western Front throughout the war. It participated in several of the most significant battles of the war, including the battles of Neuve-Chapelle, the Somme, Passchendaele and St Quentin. It suffered very heavy casualties, repeatedly losing its commanding officers during offensives; by the end of one attack in 1916, it was down to only one surviving officer and sixty men. It participated in the final Allied offensive against Germany in 1918 before returning home in May 1919.