| Manganui River | |
| Pushpin Map: | New Zealand#New Zealand North Island |
| Pushpin Map Size: | 270px |
| Pushpin Map Caption: | Mouth of the Manganui River |
| Source1 Location: | Mount Taranaki |
| Source1 Coordinates: | -39.304°N 174.0814°W |
| Mouth Location: | Waitara River |
| Mouth Coordinates: | -39.0706°N 174.2914°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 39km (24miles) |
| Progression: | Manganui River → Waitara River → North Taranaki Bight → Tasman Sea |
| Tributaries Left: | Waipuku Stream, Mangamawhete Stream, Waitepuke Stream, Ngatoro Stream, Mangatiti Stream, Mangapotoa Stream |
| Tributaries Right: | Te Popo Stream, Mangaotea Stream, Mākara Stream |
| Waterfalls: | Curtis Falls |
Manganui River is a river that flows through the Taranaki Region of New Zealand's North Island. It initially flows east from its sources on the slopes of Taranaki/Mount Egmont, turning north close to Midhirst and joining with the waters of the Waitara River ten kilometres from the North Taranaki Bight coast.