42nd Battalion
42nd Battalion may refer to:
- The Robin Hood Battalion (42nd (The Robin Hoods, Sherwood Foresters) Anti-Aircraft Battalion), a unit of the United Kingdom Army
- 42nd (East Lancashire) Division (42 Battalion Machine Gun Corps), a unit of the United Kingdom Army
- 42 Commando, a unit of the United Kingdom Royal Marine Corps
- 42nd Battalion (Australia), a unit of the Australian Army which served in World War I and World War II.