- DUN stands for Dial-Up Networking
- DUN stands for Dunsmuir (Amtrak station code; Dunsmuir, CA)
- DUN stands for Dewan Undangan Negeri (Malay: State Legislative Assembly)
- DUN stands for Derelict, Underused and Neglected (land; UK)
- DUN stands for Danske Unge Naturister (Danish: Danish Young Naturist)
- DUN stands for Douglas United Nuclear (UNC Nuclear Industries)
- DUN stands for Dorsal Ulnar Nerves
DUN