401 Squadron

401 Squadron or 401st Squadron may refer to:


 * 401 Tactical Fighter Squadron, Canada
 * 401 Squadron (Portugal)
 * 401st Tactical Airlift Squadron (JASDF), Japan
 * 401st Aero Squadron, Air Service, United States Army, see list of American aero squadrons
 * 401st Bombardment Squadron, United States Air Force
 * 401st Fighter Squadron, United States Air Force
 * VMFT-401, United States Marine Corps