Planet X is the name of planets in multiple works of science fiction and popular science. Perhaps the penultimate in uncreative planet names.
- Poul Anderson's short story "Hunters of the Sky Cave" in the collection Sir Dominic Flandry: The Last Knight of Terra, brief reference
- Edward Ashpole's non-fiction book Signatures of Life: Science Searches the Universe, p. 192
- Isaac Asimov's short story "The Deep," in his collection The Martian Way
- Paul Davies' nonfiction 2011 book The Eerie Silence
- (Desert Planet) - Buzz Lightyear of Star Command animated television series
- Leather Goddesses of Phobos 2 video game
- Cowboys vs. Aliens 2011 film
- a.k.a. Nebiru - Babylonian Legend
- Women-only planet of Queen Zombina in the parodic 1995 musical Zombies from The Beyond, See Matriarchy Planet
- Source of Alludium Phosdex (shaving cream atom) - Duck Dodgers in the 24½th Century 1953 cartoon
- The Man From Planet X 1951 film
- Planet XXX (Nude Beach Planet) - In-A-Gadda-Da-Leela episode of Futurama, June 24, 2010
- Planet Z - Buzz Lightyear of Star Command animated television series
- World X - M. John Harrison's Empty Space: A Haunting, p. 79
Community content is available under CC-BY-SA unless otherwise noted.