X3

X3 may refer to:

Films, books, games and music

• X-Men: The Last Stand, also known as X3 and X-Men 3, the third film in the comic book film series
• X3, a collection of three science fiction novellas by Gary A. Braunbeck
• X3: The Official Game, a videogame prequel to X-Men: the Last Stand
• X3: Reunion, a space simulation computer game
• X3: Terran Conflict, a sequel to X3: Reunion
• Megaman X3, the third game in Capcom's Megaman X series; a platformer game
• X3 (album), a 2004 solo album by Japanese pop singer Aya Matsuura
• X3 (group), a Chicano rap group

Transportation and technology

• HMS X3, an X class submarine of the Royal Navy
• Ilmor X3 (also known as the X³), a MotoGP race motorbike
• X-3 Stiletto, an experimental jet aircraft
• X-3 Jet Pack, a fictional rocket jet-pack from the movie Rocketeer
• X3 (train), a Swedish train
• BMW X3, the BMW Sports Activity Vehicle
• Korg X3, a synthesizer
• Foveon X3 sensor, a layered image sensor design
• XKO X3, a ERP software
• Xecuter 3, a fourth-generation Xbox modchip manufactured by TeamXecuter
• Hapag-Lloyd Express (IATA airline designator: X3), an airline doing business as TUIfly based in Hanover, Germany

Other

• X³, the mathematical cubic function
• X³, the mathematical notation representing a cube (algebra)
• X3, a subcommittee of ANSI
• X3 emoticon, indicate closed eyes "X" and cute (or cat) mouth "3", compared to ":3" or "XD"
• x3 internet slang, can be used for the verb love
• X3 is also an alternative term for the number 13 (for example, CorelDRAW X3 was released in 2006 as the 13th version of CorelDRAW)