53rd Regiment
- 53rd (City of London) Heavy Anti-Aircraft Regiment, Royal Artillery
- 53rd (Napier's) Regiment of Foot
- 53rd (Shropshire) Regiment of Foot
- 53rd Alabama Cavalry Regiment
- 53rd Anti-Aircraft Missile Regiment (Romania)
- 53rd Coast Artillery Regiment
- 53rd Division (disambiguation)
- 53rd Illinois Infantry Regiment
- 53rd Indiana Infantry Regiment
- 53rd Infantry Regiment (Imperial Japanese Army)
- 53rd Infantry Regiment (United States)
- 53rd Kentucky Mounted Infantry Regiment
- 53rd Massachusetts Infantry Regiment
- 53rd Ohio Infantry Regiment
- 53rd Pennsylvania Infantry Regiment
- 53rd Sikhs (Frontier Force)
- 53rd Wisconsin Infantry Regiment