The abbreviation MNU may refer to:
- N-Nitroso-N-methylurea, aka 1-methyl-1-nitrosourea, a mutagen
- Matariki Network of Universities, an international group of universities
- MidAmerica Nazarene University, a private Christian college located in Olathe, Kansas
- The Maldives National University, a University in Male', Maldives.
- Mianyang Normal University in Mianyang, Sichuan, China
- Museum van het Nederlandse Uurwerk, The Museum of the Dutch Clock (MNU), an overview of the history of horology in the Netherlands from the time of the invention of the pendulum clock by Christiaan Huygens.
- Multi-National United, an organization in the film District 9
- Maiden Name Unknown, a notation used in Genealogy