桐油树（学名：Jatropha curcas），又名麻风树、痲疯树、南洋油桐、黄肿树、假白榄等，为大戟科落叶灌木。其发源地在加勒比海的岛上，但葡萄牙商人把它引进了非洲和亚洲各地，现已分布在全世界的热带和亚热带地区。

桐油树的种仁含油率很高，达到40%以上，经过加工适用于生产生物柴油。在印度，桐油树被选为出产生物柴油的主要原料之一。

桐油树可生长在南北纬30度之间，在许多非洲国家被大量种植（如马里）。

它可以在荒地上种植，不与粮食作物抢耕地。

Jatropha curcas is a species of flowering plant in the spurge family, Euphorbiaceae, that is native to the American tropics, most likely Mexico and Central America. It is cultivated in tropical and subtropical regions around the world, becoming naturalized in some areas. The specific epithet, "curcas", was first used by Portuguese doctor Garcia de Orta more than 400 years ago and is of uncertain origin. Common names include Barbados nut, purging nut, physic nut, or JCL (abbreviation of Jatropha curcas Linnaeus).