Jack may refer to:

Places

* Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA

People and fictional characters

* Jack (given name), a male given name, including a list of people and fictional characters with the name * Jack (surname), including a list of people with the surname * Jack (Tekken), multiple fictional characters in the fighting game series ''Tekken'' * Jack the Ripper, an unidentified British serial killer active in 1888 * Wolfman Jack (1938–1995), a stage name of American disk jockey Robert Weston Smith * New Jack, a stage name of Jerome Young (1963-2021), an American professional wrestler * Spring-heeled Jack, a creature in Victorian-era English folklore

Animals and plants

Fish

*Carangidae generally, including: **Almaco jack **Amberjack **Bar jack **Black jack (fish) **Crevalle jack **Giant trevally or ronin jack **Jack mackerel **Leather jack **Yellow jack *Coho salmon, males called "jacks" *''Esox'' (northern pike), young called "jacks" *"Jackfish" or "jack", a western Canadian name for northern pike

Mammals

* Jack (baboon), a baboon who was the assistant to a disabled railway signalman in South Africa * Jack (cat), a Norwegian forest cat who was lost by American Airlines baggage handlers * Jack or jackass, a male donkey (''Equus africanus'')

Plants

* Jack (tree) (''Mangifera caesia''), a relative of the mango * Jack pine (''Pinus banksiana''), a North American conifer

Arts, entertainment, and media

Films

* Jack (1996 film), ''Jack'' (1996 film), a film starring Robin Williams * Jack (2004 film), ''Jack'' (2004 film), a film starring Anton Yelchin and Stockard Channing * Jack (2013 film), ''Jack'' (2013 film), a television film starring Rick Roberts and Sook-Yin Lee * Jack (2014 film), ''Jack'' (2014 film), a German film * Jack (2015 film), ''Jack'' (2015 film), an Austrian film

Games

* Jack (playing card), the lowest-ranking face card in some types of deck * Jack, a target ball used in games such as bowls * Jack, a playing piece used in the children's game called Jacks (game), jacks

Literature

* Jack (Homes novel), ''Jack'' (Homes novel), a 1990 novel by A. M. Homes * Jack (Lundell novel), ''Jack'' (Lundell novel), a 1976 novel by Ulf Lundell * Jack (Robinson novel), ''Jack'' (Robinson novel), a 2020 novel by Marilynne Robinson

Periodicals

* Jack (Italian magazine), ''Jack'' (Italian magazine), an Italian-language technology magazine * Jack (magazine), ''Jack'' (magazine), an English-language British lad mag

Music

Artists and groups

* Jack (band), a British independent pop group signed to the Too Pure label * Jack & Jack, an American an American pop-rap duo * Jack (Vietnamese singer) (born 1997), a Vietnamese pop star

Albums

* Jack (album), ''Jack'' (album), a 2010 studio album by John Farnham * Jack (EP), ''Jack'' (EP), a 1991 EP by Moose * ''Jack'', a 1984 album by Bone Orchard * ''J.A.C.K.'', a 2013 studio album by Forever the Sickest Kids

Songs

* Jack (song), "Jack" (song), a 2013 song by Breach * "Jack" (1980), a B-side song to "Tell The Children" by Sham 69 on the album Kings & Queens (Sham 69 album), ''Kings & Queens'' * "Jack" (1984), a song and single by Bone Orchard * "Jack" (2001), a song by Iced Earth from their album Horror Show (album), ''Horror Show'' (2001) * "Jack" (1983), a song and single by Machinations (band) * "Jack" (1983), a song and single by Mighty Gabby * "Jack", song by Pixie Lott from the ''Turn It Up (Pixie Lott album), Turn It Up'' (2009) album * "The Jack", a song by AC/DC originally on the album ''T.N.T. (album), T.N.T.'' (1975)

Television

* Jack (TV series), ''Jack'' (TV series), a 3D-animated series broadcast by TVOntario * Jack TV, a general entertainment channel in the Philippines (cable)

Other uses in arts, entertainment, and media

* Jack (hero), an archetypal Cornish and English hero and stock character * Jack FM, a radio format and brand

Military

* Jack (flag), a national maritime flag flown by warships, e.g., **Union Jack * Jack, the Allied code-name of the Japanese Mitsubishi J2M fighter of World War II

Technology

Computing and software

* Jack (CAD software), a 3-D ergonomics and human factors CAD package * Jack (human modeling), a human modeling and simulation system * JACK Audio Connection Kit, a computer sound server * JACK Intelligent Agents, a multi-agent platform written in Java

Electrical interfaces

* Electrical connector#Plug and socket connectors, Electrical connector, or "wall jack", a socket (often panel-mounted) intended to accept a plug * Phone connector (audio), commonly known as "audio jack", or "jack plug", or "phone jack" * Registered jack, a standardized telecommunication network interface for connecting voice and data equipment

Mechanical tools

* Jack (device), a device used to lift heavy objects **Jackscrew, a device used to support heavy objects at various heights **Pallet jack, a device with two forks used to lift and move pallets; the powered version is known as a forklift **Strand jack, used in construction and engineering, and is capable of lifting hundreds of tonnes * Boot jack, a device for removing boots * Jack plane, a tool for smoothing wood * Roasting jack, a device for turning a spit

Other uses

* Jack (mascot), the mascot of Jack in the Box restaurants * Cracker Jack and Cracker Jack'D, snack foods * Jack Daniel's, a Tennessee whiskey distillery, whose product is sometimes referred to as "Jack" * Jack of plate or jack, a type of armor * Jack's (store), a British Discount supermarket chain * Monterey Jack, a variety of cheese * Sailor, "jack" in obsolete usage * Sailor Jack, he and his dog Bingo are the mascots for Cracker Jack snack food * Yukon Jack (liqueur), a Canadian whisky with honey * Jack Tar, term for a sailor