Cthulhu is a fictional cosmic entity created by horror author H. P. Lovecraft
Cthulhu may also refer to:
- Cthulhu (2000 film), an Australian horror film by Damian Heffernan
- Cthulhu (2007 film), an American horror film
- H. P. Lovecraft's Cthulhu: The Whisperer in Darkness, a 1990s comics mini-series
- "Cthulhu", a song by Therion from Beyond Sanctorum
- "Cthulhu", a song by The Acacia Strain from "Continent"