| Ōtira River | |
| Pushpin Map: | New Zealand#New Zealand South Island |
| Pushpin Map Size: | 270px |
| Pushpin Map Caption: | Mouth of the Ōtira River |
| Source1: | Mount Rolleston |
| Source1 Coordinates: | -42.9022°N 171.5231°W |
| Mouth Location: | Taramakau River |
| Mouth Coordinates: | -42.762°N 171.633°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 20km (10miles) |
| Progression: | Ōtira River → Taramakau River → Tasman Sea |
| Tributaries Left: | Curtis Creek, Kea Creek, Park Creek, Hodge Creek, Rolleston River, Goat Creek, Kellys Creek |
| Tributaries Right: | Pegleg Creek, Candys Creek, Reid Falls, Wesley Creek, Barrack Creek, Deception River, Paratu Stream |
| Bridges: | Ōtira Viaduct, Wallace Point Bridge, Yorkeys Point Bridge, Ōtira River Bridge, Morrison Footbridge |
The Ōtira River is located in the central South Island of New Zealand. It rises on the slopes of Mount Rolleston in the Southern Alps, and flows north for, passing through the town of Otira before joining the Taramakau River. The Taramakau's outflow is into the Tasman Sea, south of Greymouth.
The valley of the Otira River forms the northwestern approach to Arthur's Pass, one of the three main passes across the Southern Alps.