may refer to:
- Janus (mythology), the two-faced Roman god of gates, doors, doorways, beginnings, and endings.
- Janus (moon), a moon of Saturn.
- Janus Patera, a shallow volcanic crater on Io, a moon of Jupiter.
- Janus (simulation), a military combat simulation first developed in the late 1970s by the Lawrence Livermore National Laboratory's Combat Simulation Laboratory.
- Society of Janus, a San Francisco based BDSM education and support group.
- Janus Capital Group, an investment company based in Denver, Colorado.
- Zündapp Janus, a bubble car model by Zündapp.
- a Janus word, or auto-antonym: a word with two opposite meanings.
- Janus (TV series), A television series created by the Australian Broadcasting Commission with two story lines: the criminal family being prosecuted and the police/judicial process.
- Schempp-Hirth Janus, a two-seater glider.
- HMS Janus, a name used by British naval ships.
Film and music
- Janus Films, an American film distribution company.
- Janus Records, a record label.
- Janus (band), an orchestral darkwave group.
- Janus, the criminal organization in the James Bond movie GoldenEye.
- The Janus Project, a taboo cloning project in the movie Judge Dredd.
- "Janus", a song from the album Out and About with the Gone Jackals by hard rock group The Gone Jackals.
- "Janus" appears on the CD Inner Journeys: Myth + Legends by Cusco
Literature and comics
- Janus: A Summing Up, a book by Arthur Koestler.
- Janus (comics), a superhero in the DC Comics universe.
- Janus (Marvel Comics), a superhero in the Marvel Comics universe and an enemy of Marvel Comics' Dracula.
- The Janus Directive, a DC Comics crossover.
- Janus (Stargate), an "Ancient" scientist in the TV series Stargate Atlantis and Stargate SG-1.
- Janus (Angels and Demons), the antagonist in the novel Angels and Demons.
- Janus, a French poetry magazine published in Paris by Elliott Stein from 1950 to 1961.
- Janus Publishing, a British publishing company known for publishing the work of previously unpublished authors.
- Janus, a short story by Ann Beattie.
Games and gaming
- Janus Island, an island of the Palmer Archipelago, Antarctica.
- Janus Lake (Ontario), Canada.
- Janus Lake (Washington), Snohomish County, Washington.
- Mont Janus, France.
- Mount Janus (Antarctica)
- Mount Janus (Newfoundland), Newfoundland and Labrador, Canada.
- Mount Janus (Svalbard), Norway.
- Janus Peak, British Columbia, Canada.
- Janus-faced molecule, used to describe a molecule whose effects on organisms can vary between beneficial and toxic.
- Janus Experiments, a series of experiments on radio-sensitivity in mice and dogs.