123rd
- 123 (number)
- 123rd Battalion (Royal Grenadiers), CEF
- 123rd Contingency Response Group
- 123rd Delaware General Assembly
- 123rd IOC Session
- 123rd Illinois Volunteer Infantry Regiment
- 123rd Outram's Rifles
- 123rd Regiment of Foot (1762)
- 123rd Regiment of Foot (Loyal Lincolnshire)
- 123rd Street station
- 123rd meridian east
- 123rd meridian west
- AD 123
- Ohio 123rd General Assembly
- Polish 123rd Fighter Escadrille