Planet X (disambiguation)
- Duck Dodgers in the 24½th Century
- Groot
- How Time Flys
- Hypothetical Solar System objects
- Invasion of Astro-Monster
- Jimmy Johnson (bassist)
- List of hypothetical Solar System objects
- Nibiru cataclysm
- Ninth planet (disambiguation)
- Operation Planet X
- Packages from Planet X
- Plan-It-X Records
- Planet Nine
- Planet X
- Planet X (Derek Sherinian album)
- Planet X (Helios Creed album)
- Planet X (Star Trek)
- Planet X (band)
- Planet X (comics)
- Planet X Limited
- Planet X Television
- Tenth planet (disambiguation)
- Trans-Neptunian object