- Source: 51st Regiment
- Marion T. Anderson
- 51st Regiment
- 51st (2nd Yorkshire West Riding) Regiment of Foot
- 49th Field Artillery Regiment, RCA
- 51st New York Infantry Regiment
- 51st Regiment of Foot (disambiguation)
- 51st Massachusetts Infantry Regiment
- King's Own Scottish Borderers
- 51st Highland Volunteers
- Pepperrell's Regiment
- 51st Indiana Infantry Regiment
51st Regiment or 51st Infantry Regiment may refer to:
51st Regiment of Foot (disambiguation), several units of the British Army
51st Highland Volunteers, a unit of the British Army
51st Infantry Regiment (United States)
51st Armoured Regiment (India)
51st Coast Artillery Regiment, a unit of the United States Army
51st (Leeds Rifles) Royal Tank Regiment
51st (Highland) Searchlight Regiment, Royal Artillery
51st (London) Heavy Anti-Aircraft Regiment, Royal Artillery
51st (Westmoreland and Cumberland Yeomanry) Field Regiment, Royal Artillery
51st Sikhs (Frontier Force), a unit of the British Indian Army
Union Army (American Civil War):
51st Illinois Infantry Regiment
51st Indiana Infantry Regiment
51st Regiment Massachusetts Volunteer Infantry
51st New York Volunteer Infantry
51st Ohio Infantry
51st Pennsylvania Infantry Regiment
51st Wisconsin Volunteer Infantry Regiment
51st United States Colored Infantry Regiment
See also
51st Division (disambiguation)