| Waikōau River | |
| Pushpin Map: | New Zealand Fiordland#New Zealand South Island#New Zealand |
| Pushpin Map Size: | 270px |
| Pushpin Map Caption: | Mouth of Waikōau River |
| Source1 Coordinates: | -46.0856°N 167.3178°W |
| Mouth Location: | Te Waewae Bay |
| Mouth Elevation: | 0m (00feet) |
| Mouth Coordinates: | -46.1496°N 167.445°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Subdivision Type2: | Region |
| Subdivision Name2: | Southland |
| Subdivision Type3: | District |
| Subdivision Name3: | Southland |
The Waikōau River is a river in southern Fiordland, New Zealand. Since 21 June 2019 the official name has been Waikōau River. Waikōau River North Branch has been the official name of a tributary, which joins the river about a kilometre from the sea, since 19 December 2019. Rising north of the Hump Ridge, it flows south-eastward into Te Waewae Bay.
The New Zealand Ministry for Culture and Heritage gives a translation of "waters of the shag" for Maori: Waikōau.[1]
There is also a Waikoau River in Hawke's Bay, which flows into the Aropaoanui River.