| Waiuna Lagoon | |
| Location: | Big Bay, Southland, South Island |
| Coords: | -44.304°N 168.138°W |
| Inflow: | Dry Awarua River |
| Outflow: | Awarua River |
| Basin Countries: | New Zealand |
| Elevation: | 15m (49feet) |
Waiuna Lagoon is a lake in the Southland Region of New Zealand's South Island, just inland from Big Bay. It is 15 metres above sea level, and is drained by the Awarua River.