403rd or 403d may refer to:

• 403d Bombardment Squadron, inactive United States Air Force unit
• 403d Operations Group, the operational flying component of the United States Air Force Reserve 403d Wing
• 403d Wing, unit of the United States Air Force assigned to the Air Force Reserve Command
• 403rd Infantry Brigade, known officially as the Peacemaker Brigade, one of the brigades of the Philippine Army

See also[edit]

• 403 (number)
• 403, the year 403 (CDIII) of the Julian calendar
• 403 BC