NIW
| Acronym | Definition |
|---|---|
| NIW | National Interest Waiver |
| NIW | Northern Ireland Water (UK) |
| NIW | Network Install Wizard |
| NIW | Nieuw Israelietisch Weekblad (Dutch: New Israelite Weekly; Netherlands) |
| NIW | Network Installation Wizard (Microsoft) |
| NIW | National Institute of Webographers (real estate professionals) |
| NIW | Naval Inshore Warfare |
| NIW | Night In Weather |