84th Regiment

84th Regiment or 84th Infantry Regiment may refer to:


 * 84th Regiment of Foot (1759), a unit of the British Army, active from 1759 to 1765, which served entirely in British India
 * 84th Regiment of Foot (Royal Highland Emigrants), a unit of the British Army, active from 1775 to 1784, which served in the American Revolutionary War
 * 84th (York and Lancaster) Regiment of Foot, a unit of the British Army, active from 1793 to 1881, which served in the Napoleonic Wars and in India
 * 84th Infantry Regiment (Philippine Commonwealth Army), a unit of the Philippine Commonwealth Army, active from 1942 to 1946, which served in the Second World War


 * American Civil War
 * 84th Illinois Volunteer Infantry Regiment, a unit of the Union (North) Army
 * 84th Regiment Indiana Infantry, a unit of the Union (North) Army
 * 84th New York Volunteer Infantry Regiment, a unit of the Union (Northern) Army
 * 84th Ohio Infantry, a unit of the Union (Northern) Army
 * 84th Pennsylvania Infantry, a unit of the Union (Northern) Army