LNU can refer to:
- Last Name Undefined.
- League of Nations Union
- Linnaeus University
- Lviv University
- Liaoning Normal University
- Leyte Normal University
- Last Name Unknown - see Fnu Lnu
- The Norwegian Children and Youth Council, Landsrådet for Norges barne- og ungdomsorganisasjoner
- Lnu or Mi'kmaq people, a First Nations People of North America