Wai-O-Tapu (Māori for "sacred waters") is an active geothermal area at the southern end of the Okataina Volcanic Centre, just north of the Reporoa caldera, in New Zealand's Taupo Volcanic Zone. It is 27 kilometres south of Rotorua.
The area has many hot springs noted for their colourful appearance, in addition to the Lady Knox Geyser, Champagne Pool, Artist's Palette, Primrose Terrace and boiling mud pools. The geothermal area covers 18 square kilometres.