The purple mangosteen (Garcinia mangostana), colloquially known simply as mangosteen, is a tropical evergreen tree believed to have originated in the Sunda Islands and the Moluccas of Indonesia. It grows mainly in Southeast Asia, and also in tropical South American countries such as Colombia, in the state of Kerala in India and in Puerto Rico, where the tree has been introduced. The tree grows from 6 to 25 m (19.7 to 82.0 ft) tall. The fruit of the mangosteen is sweet and tangy, juicy, somewhat fibrous, with fluid-filled vesicles (like the flesh of citrus fruits), with an inedible, deep reddish-purple colored rind (exocarp) when ripe.

In each fruit, the fragrant edible flesh that surrounds each seed is botanically endocarp, i.e., the inner layer of the ovary. Seeds are almond-shaped and sized.

The purple mangosteen belongs to the same genus as the other, less widely known, mangosteens, such as the button mangosteen (G. prainiana) or the charichuelo (G. madruno).

A description of mangosteen was included in the Species Plantarum by Linnaeus in 1753.