NIWA
| Acronym | Definition |
|---|---|
| NIWA | Nintendo Independent Wiki Alliance |
| NIWA | National Institute of Water and Atmospheric Research, Ltd (New Zealand) |
| NIWA | Naval Information Warfare Activity |
| NIWA | Namibian Information Workers' Association |
| NIWA | North Island Woodlot Association (British Columbia, Canada) |
| NIWA | Northwest Indiana Woodworkers Association (est. 1990) |
| NIWA | National Internet Wrestling Association |