Grapefruit (Citrus ® paradisi) is a subtropical citrus tree known for its sour to semi sweet bitter fruit. Grapefruit is a hybrid of Barbados origin. It is an occasional introduction of two species, C. sinensis and grapefruit or C. maxima, both of which were introduced from Asia in the 17th century. When it was found, it was called the forbidden fruit. The grapefruit was also mistaken.

Grapefruit's name implies clusters of fruit on trees, which usually look like grapes.

Grapefruit is a kind of ancient hybrid that originated from Asia. The other is C. maxima. One story about the origin of the fruit is that Captain shaddock brought the grapefruit to Jamaica and produced the first fruit. However, it is likely to be a natural hybrid of two plants within a period of time after their introduction.