Kōwhai are small, woody legume trees in the genus Sophora native to New Zealand. There are eight species, S. microphylla being the most common. Kowhai trees grow throughout the country and are a common feature in New Zealand gardens. Outside of New Zealand, Kowhai tend to be restricted to mild temperate maritime climates.

The name kōwhai comes from the Māori word for yellow—a reference to the colour of the flower. It is also called kōhai in some areas. Usually the name is spelled as kowhai.

Despite having no official status as such, the blooms of the kowhai are widely regarded as being New Zealand's national flower.