| Kopuaranga River | |
| Mouth Location: | confluence with the Ruamahanga River |
| Progression: | Ruamahanga – Cook Strait |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 28km (17miles) |
The Kopuaranga River (officially Kōpuaranga River) is a river of the Wairarapa, in New Zealand's North Island. It flows generally south from rough hill country southwest of Eketāhuna, reaching its outflow into the Ruamahanga River 5km (03miles) north of Masterton.
In December 2019, the approved official geographic name of the river was gazetted as "Kōpuaranga River".[1]