- DNU stands for Do Not Understand (used in reviewing academic papers)
- DNU stands for Do Not Use
- DNU stands for Decreto de Necesidad y Urgencia (Argentina)
- DNU stands for Dr. Nausch Unternehmensberatung (Germany)
- DNU stands for Dansk Naturist Union (Danish: Danish Naturist Union)
- DNU stands for Delta Nu Alpha
- DNU stands for Department of Natural Unicorns (fictional; Lake Superior State University; Michigan)
DNU