381st may refer to:
381st Bombardment Squadron, inactive United States Air Force unit 381st Fighter Squadron or 18th Reconnaissance Squadron, squadron of the United States Air Force 381st Intelligence Squadron, intelligence unit located at Joint Base Elmendorf-Richardson, Alaska 381st Training Group at Vandenberg AFB, California provides training for the nation's space and intercontinental ballistic missile (ICBM) operations
See also 381 (number) 381, the year 381 (CCCLXXXI) of the Julian calendar 381 BC