| Lake Maraetai | |
| Pushpin Map: | North Island |
| Pushpin Map Alt: | Location of Lake Maraetai |
| Location: | North Island |
| Coords: | -38.3664°N 175.7858°W |
| Lake Type: | Reservoir |
| Basin Countries: | New Zealand |
| Area: | 4.4km2 |
| Max-Depth: | 75m (246feet) |
Lake Maraetai is one of several artificial lakes formed as part of a hydroelectricity scheme on the Waikato River in the North Island of New Zealand. It is located southeast of Hamilton, close to the town of Mangakino.
It is a relatively small lake, covering only, but it is deep at some points, and the powerhouses (Maraetai I and Maraetai II) at its northern end generate of power.