X3

X3 may refer to:

• X-Men: The Last Stand, also known as X3 and X-Men 3, the third film in the comic book film series
• XXX: Return of Xander Cage, a 2017 American film directed by D. J. Caruso

• X3, a collection of three science fiction novellas by Gary A. Braunbeck

• X3 (group), a short-lived Australian girl group, circa 2000
• X3 (album), a 2004 solo album by Japanese pop singer Aya Matsuura

• X-Men: The Official Game, a 2006 videogame prequel to X-Men: The Last Stand
• X³: Reunion, a space simulation computer game
  • X³: Terran Conflict, a sequel to X³: Reunion
    • X³: Albion Prelude, an addon to X³: Terran Conflict
• Dance Dance Revolution X3, a 2011 music video game by Konami
• Mega Man X3, a 1995 platforming game in Capcom's Mega Man X series

• Korg X3, a synthesizer

• Kyocera X3, an Android One smartphone by Kyocera
• Mobile phone models by Nokia
  • Nokia X3-00 or Nokia X3
  • Nokia X3 Touch and Type or Nokia X3-02

• Foveon X3 sensor, a layered image sensor design

• Cygnus X-3, a binary x-ray source in the sky

• X3, one former name of a subcommittee of ANSI, now International Committee for Information Technology Standards (INCITS)
• X3 (code) aka Excess-3, a binary code also termed Stibitz code
• XKO X3, an ERP software

• X³, the mathematical cubic function

• Douglas X-3 Stiletto, an experimental jet aircraft
• Eurocopter X3, an experimental compound helicopter

• Beijing X3, a Chinese subcompact crossover SUV
• BMW X3, a German compact SUV
• Cowin X3, a Chinese compact SUV
• Geely Vision X3, a Chinese subcompact crossover
• Jingyi X3, a Chinese subcompact crossover

• X3 (New York City bus)
• X3, a Metrobus route in Washington, D.C. U.S.

• TUI fly Deutschland (IATA airline designator X3 since 2007)
• Hapag-Lloyd Express (IATA airline designator X3, 2002-2007)

• Ilmor X3 (also termed the X³), a MotoGP race motorbike

• X-3, the Prospero (satellite) launched by the UK in 1971

• X3 (train), a Swedish train built by Alstom

• HMS X3, an X-class submarine of the Royal Navy

• 3X (disambiguation)