山竹（学名：Garcinia mangostana），又名莽吉柿、山竺、山竹子、倒捻子、凤果，热带常绿乔木，为金丝桃科藤黄属下的一个种。原产于马来群岛中的巽他群岛和摩鹿加群岛，由于盛产于南洋热带地区，有“热带果后”之称。在马来西亚、新加坡和泰国，榴梿和山竹被视为“夫妻果”，故此相对于称为「果王」的榴梿而言，山竹就是「果后」。

山竹同属的主要水果包括钮扣山竹（Garcinia prainiana）和柠檬山竹（Garcinia madruno），近缘种是福木（Garcinia subelliptica）。

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, southwest India and other tropical areas such as Puerto Rico and Florida, 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.