84th Regiment
- 84th (York and Lancaster) Regiment of Foot
- 84th Division (disambiguation)
- 84th Illinois Volunteer Infantry Regiment
- 84th New York Volunteer Infantry Regiment
- 84th Ohio Infantry
- 84th Pennsylvania Infantry
- 84th Regiment Indiana Infantry
- 84th Regiment of Foot (1759)
- 84th Regiment of Foot (Royal Highland Emigrants)
- 84th Squadron (disambiguation)
- 84th Wing (disambiguation)
- American Revolutionary War
- British Army
- Philippine Commonwealth Army