| Monowai River | |
| Pushpin Map: | New Zealand Fiordland#New Zealand South Island#New Zealand |
| Pushpin Map Size: | 270px |
| Pushpin Map Caption: | Mouth of the Monowai River |
| Source1 Location: | Lake Monowai |
| Source1 Coordinates: | -45.8111°N 167.5242°W |
| Source1 Elevation: | 180m (590feet) |
| Mouth Coordinates: | -45.7756°N 167.6167°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Progression: | Monowai River → Waiau River → Foveaux Strait |
The Monowai River is a river in New Zealand, draining Lake Monowai into the Waiau River and feeding the Monowai Power Station.