DEN may refer to:
- The IOC and FIFA country code for Denmark
- Denbighshire (historic), traditional county in Wales, Chapman code
- Denver, the capital of and largest city in the U.S. state of Colorado
- Denver International Airport's IATA code
- Stapleton International Airport's former IATA code
- Denver Union Station's Amtrak station code
- Denver Broncos, the city's National Football League team
- Denver Nuggets, the city's National Basketball Association team
- Dennis railway station, Melbourne
- Digital Entertainment Network
- Diethylnitrosamine
- Denormal number