83rd Regiment or 83rd Infantry Regiment may refer to:
Royal Irish Regiment (1992), a unit of the British Army which carries on the lineage of the 83rd Ulster Defense Regiment 83rd Regiment of Foot (disambiguation), several units of the British Army 83rd Wallajahbad Light Infantry, a unit of the British Indian Army
83rd Field Artillery Regiment, United States 83rd Fighter Aviation Regiment, later Fighter-Bomber regiment, a unit of the Yugoslav Air Force
American Civil War regiments: 83rd Illinois Volunteer Infantry Regiment, a unit of the Union (Northern) Army 83rd Indiana Infantry Regiment, a unit of the Union (Northern) Army 83rd New York Volunteer Infantry Regiment, a unit of the Union (Northern) Army 83rd Ohio Infantry, a unit of the Union (Northern) Army 83rd Pennsylvania Infantry, a unit of the Union (Northern) Army
See also 83rd Division (disambiguation) 83rd Squadron (disambiguation)