Muramasa Sengo was a famous Japanese swordsmith.
Muramasa may also refer to:
- Muramasa: The Demon Blade, the 2009 video game by Vanillaware.
- Muramasa, one of the primary antagonists of the Zanpakutō Unknown Tales arc, Muramasa is a mysterious former zanpakutō responsible for causing a full-scale Zanpakutō Rebellion to take place within the Soul Society, in the hopes of finding a way to unseal his master from his prison.