XX

For technical reasons, "X_X" and similar titles redirect here. For the keyboard symbol, see List of emoticons.

XX or xx may refer to:

• 20 (number), Roman numeral XX

Genetics

• An organism with two X chromosomes, in the XY sex-determination system (of humans, as well as some other animals and some plants) and the XO sex-determination system (of some animals):
  • Usually female, producing ova gametes that fuse with the male gamete during sexual reproduction
  • XX male syndrome (AKA de la Chapelle syndrome), a rare congenital intersex condition

Arts and media

• XX (film), a 2017 anthology horror movie
• "XX" (CSI), a 2004 episode (S4 E17 / #86) of CSI: Crime Scene Investigation
• XX, the production code for the 1969 Doctor Who serial The Seeds of Death
• XX (web series), a 2020 South Korean online television drama
• XX (organization), a fictional organisation in the XIII comics (adapted into a video game, film, and TV series)
• XX (novel), a 2020 novel by Rian Hughes
• Les XX, a group of twenty Belgian painters

Music

Bands

• The xx, an English indie rock band
• X_______X (band), an American no wave band

Albums

• Toto XX, by Toto, 1998
• XX (Mushroomhead album), 2001
• xx (The xx album), 2009
• XX (Great Big Sea album), 2012
• XX – Two Decades of Love Metal, by HIM, a 2012 compilation album
• XX (O.A.R. album), 2016
• XX (Mino album), 2018
• XX (Note-oriety album), 2018
• [+ +], a 2018 EP by Loona, repackaged as [X X] or [× ×] in 2019
• XX (Brian Culbertson album), 2020
• XX (Il Divo album), 2024
• XX (Fally Ipupa album), 2026

Songs

• "xx", from Expectations (Hayley Kiyoko album), 2018
• "XX", from Ferxxo (Vol 1: M.O.R) by Feid, 2020

Military

• XX System or Double-Cross System, a British deception operation in the Second World War
• XX Bomber Command, an inactive United States Air Force unit
• XX Corps (disambiguation)
• Legio XX Valeria Victrix, a legion of the Roman Empire

Computing

• xx, to express exponentiation in the initial version of the FORTRAN programming language
• .xx ("dot ex ex"), a placeholder for an Internet country code top-level domain

Other uses

• Dos Equis or Siglo XX, a brand of Mexican beer

See also

• XX gonadal dysgenesis, a type of female hypogonadism resulting in non-functioning ovaries
• All pages with titles containing XX
• All pages with titles containing ex ex
  • Ex-ex-gay, a social movement
  • United States Exploring Expedition of 1838–1842 to the Pacific Ocean and surrounding lands
  • Ex Ex Lovers, a 2025 Philippine romantic comedy film
• 20 (disambiguation)
• Double Cross (disambiguation)
• X (disambiguation)
• XXX (disambiguation)
• XXXX (disambiguation)