83rd Regiment
- 83rd Division (disambiguation)
- 83rd Field Artillery Regiment
- 83rd Fighter Aviation Regiment
- 83rd Illinois Volunteer Infantry Regiment
- 83rd Indiana Infantry Regiment
- 83rd New York Volunteer Infantry Regiment
- 83rd Ohio Infantry
- 83rd Pennsylvania Infantry
- 83rd Regiment of Foot (disambiguation)
- 83rd Squadron (disambiguation)
- 83rd Wallajahbad Light Infantry
- Royal Irish Regiment (1992)