23rd Regiment
- 23 Engineer Regiment (Air Assault) (United Kingdom)
- 23rd Arkansas Infantry Regiment
- 23rd Coast Artillery (United States)
- 23rd Connecticut Infantry Regiment
- 23rd Dragoon Regiment (France)
- 23rd Field Artillery Regiment (United States)
- 23rd Field Regiment, RCA
- 23rd Illinois Infantry Regiment
- 23rd Indiana Infantry Regiment
- 23rd Infantry Regiment (United States)
- 23rd Iowa Volunteer Infantry Regiment
- 23rd Light Dragoons
- 23rd Marching Regiment of Foreign Volunteers
- 23rd Marine Regiment (United States)
- 23rd Michigan Infantry Regiment
- 23rd Missouri Infantry Regiment
- 23rd New York Infantry Regiment
- 23rd Ohio Infantry
- 23rd Pennsylvania Infantry
- 23rd Regiment Armory
- 23rd Regiment Kentucky Volunteer Infantry
- 23rd Regiment Massachusetts Volunteer Infantry
- 23rd Regiment of Bombay Light Infantry
- 23rd Regiment of Foot
- 23rd Regiment, Royal Australian Artillery
- 23rd Tennessee Infantry Regiment
- 23rd Virginia Cavalry
- 23rd Wisconsin Volunteer Infantry Regiment