FJ

FJ may refer to:

• Holden FJ, an Australian car
• femtojoule (fJ), an SI unit of energy equal to 10⁻¹⁵ joules
• Fiji (ISO 3166-1 alpha-2 country code)
  • .fj, the country code top level domain (ccTLD) for Fiji
• the IATA code for Air Pacific
• the racing class Formula Junior
• the FJ Fury, an early Cold War fighter aircraft of the US Navy
• the Flying Junior, a sailing dinghy
• the Toyota FJ Cruiser
• Finger Joint Boards
• an abbreviation of Fallschirmjäger (German paratroopers)
• The FASEB Journal