Alien

Alien (law), a person in a country who is not a national of that country
- Enemy alien, the above in times of war
Extraterrestrial life, life which does not originate from Earth
- Specifically, a lifeform with extraterrestrial intelligence
- For fictional extraterrestrial life, see Extraterrestrials in fiction
Introduced species, a species not native to its environment

Alien(s), or The Alien(s) may also refer to:

Science and technology

Alien (franchise), a media franchise
- Xenomorph, the titular alien in the franchise

Alien (film), a 1979 film by Ridley Scott
- Aliens (film), second film in the franchise from 1986 by James Cameron
- Alien 3, third film in the franchise from 1992 by David Fincher
- Alien Resurrection, fourth film in the franchise from 1997 by Jean-Pierre Jeunet
- Alien vs. Predator (film), fifth film in the franchise from 2004 by Paul W. S. Anderson
- Aliens vs. Predator: Requiem, sixth film in the franchise from 2007 by the Brothers Strause
- Prometheus (2012 film), seventh film in the franchise from 2012 by Ridley Scott
- Alien: Covenant, eighth film in the franchise from 2017 by Ridley Scott
Alien 2: On Earth, a 1980 unofficial sequel of the 1979 Alien film
Alien Visitor (also titled Epsilon) (1995 film) Australian–Italian science fiction film by Rolf de Heer
The Alien (2016 film), a 2016 Mexican film
The Alien (unproduced film), an incomplete 1960s Indian–American film
Alienoid, a 2022 South Korean film

Alien novels, an extension of the Alien franchise
Aliens: Colonial Marines Technical Manual, a 1995 book by Lee Brimmicombe-Wood, a guide to the fictional United States Colonial Marines
Aliens (Tappan Wright novel), a 1902 novel by Mary Tappan Wright
Aliens! (anthology) a 1980 anthology of science fiction edited by Gardner Dozois and Jack Dann
The Alien (novel), the eighth book in the Animorphs series by Katherine Applegate
The Aliens (play), a 2010 play by Annie Baker

Alien (band), a 1980s Swedish rock group
The Aliens (Australian band), a 1970s new wave group
The Aliens (Scottish band), a 2005–2008 rock group
The Aliens, the backing band for the American musician Jared Louche on his 1999 solo debut album Covergirl

"Alien" (Britney Spears song), 2013
"Alien" (Jonas Blue and Sabrina Carpenter song), 2018
"Alien", a song by Atlanta Rhythm from the album Quinella, 1981
"Alien", a song by Bush from the album Sixteen Stone, 1994
"Alien", a song by Dead Letter Circus from the EP Dead Letter Circus, 2007
"Alien", a song by Erasure from the album Loveboat, 2000
"Alien", a song by Japan from the album Quiet Life, 1979
"Alien", a song by Lamb from the album Fear of Fours, 1999
"Alien", a song by Nerina Pallot from the album Dear Frustrated Superstar, 2001
"Alien", a song by P-Model from the album Landsale, 1980
"Alien", a song by Pennywise from the album Straight Ahead, 1999
"Alien", a song by Stray Kids from the album SKZ-Replay, 2022
"Alien", a song by Structures from the album Life Through a Window, 2014
"Alien", a song by the National from the album First Two Pages of Frankenstein, 2023
"Alien", a song by Third Day from the album Conspiracy No. 5, 1997
"Alien", a song by Thriving Ivory from the album Thriving Ivory, 2003
"Alien", a song by Tokio Hotel from the album Humanoid, 2009
"Alien", a 2018 song by Beach House
"Alien", a 2020 song by Lee Su-hyun
"Alien", a 2020 song by Dennis Lloyd
"Aliens" (song), a 2017 song by Coldplay
"Aliens", a 1984 song by Warlord
"The Alien", a song by Dream Theater from the album A View from the Top of the World, 2021

Alien (1982 video game), a 1982 maze game based on the 1979 film
Alien (1984 video game), based on the film
Alien: Isolation, a 2014 video game based on the Alien science fiction horror film series
Aliens (1982 video game), a text-only clone of Space Invaders written for the CP/M operating system on the Kaypro computer
Aliens (1990 video game), a game by Konami, based on the sequel of the film

Alien (Armenian TV series), a 2017 melodrama series
Alien (American TV series), an upcoming science fiction horror television series
Alien (sculpture), a 2012 work by David Breuer-Weil, in Mottisfont, Hampshire, England
Aliens (Dark Horse Comics line)
The Aliens (TV series), 2016 British sci-fi television series
"Aliens" (Roseanne), a 1992 television episode