Lake Taupo, often spelled Taupō, is a lake in the North Island of New Zealand. It is in the caldera of the Taupo Volcano. The lake is the namesake of the town of Taupō, which sits on a bay in the lake's north-eastern shore. With a surface area of 616 square kilometres, it is the largest lake by surface area in New Zealand, and the second largest freshwater lake by surface area in geopolitical Oceania after Lake Murray in Papua New Guinea. Motutaiko Island lies in the south east area of the lake.
Lake Taupo has a perimeter of approximately 193 kilometres and a maximum depth of 186 metres. It is drained by the Waikato River, and its main tributaries are the Waitahanui River, the Tongariro River, and the Tauranga Taupo River. It is a noted trout fishery with stocks of introduced brown and rainbow trout.
The level of the lake is controlled by Mercury Energy, the owner of the eight hydroelectric dams on the Waikato River downstream of Lake Taupo, using gates built in 1940–41. The gates are used to reduce flooding, conserve water and ensure a minimum flow of 50 m³/s in the Waikato River.