| Motunau River | |
| Mouth Location: | Pegasus Bay |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 18km (11miles) |
The Motunau River is a river of the north Canterbury region of New Zealand's South Island. It flows south-east from coastal hills south-west of Cheviot, reaching the Pacific Ocean at Motunau Beach at the northern tip of Pegasus Bay.