In Māori mythology, taniwha are large supernatural beings that live in deep pools in rivers, dark caves, or in the sea, especially in places with dangerous currents or deceptive breakers . They may be considered highly respected kaitiaki of people and places, or in some traditions as dangerous, predatory beings, which for example would kidnap women to have as wives.

Māori mythology and Māori traditions are two major categories into which the remote oral history of New Zealand's Māori may be divided. Māori myths concern tales of supernatural events relating to the origins of what was the observable world for the pre-European Māori, often involving gods and demigods. Māori tradition concerns more folkloric legends often involving historical or semi-historical forebears. Both categories merge in whakapapa to explain the overall origin of the Māori and their connections to the world which they lived in.