NIU
| Acronym | Definition |
|---|---|
| NIU | Northern Illinois University |
| NIU | Niue (ISO Country code) |
| NIU | Northland International University (Wisconsin) |
| NIU | Network Interface Unit |
| NIU | Not in Use |
| NIU | Naval Intelligence Unit (US Navy) |
| NIU | National Interdiction Unit (Afghanistan) |
| NIU | National I-Lan University (Taiwan) |
| NIU | Nitrogen Inerting System |
| NIU | Nagoya Imperial University (now Nagoya University; Japan) |
| NIU | NATO Interface Unit |
| NIU | Nacelle Interface Unit |
| NIU | Northern International University (Magadan, Russia) |