Background. Oxalis corniculata L. is a weed with a worldwide distribution and unknown origin. Though it belong to a section of the genus from South American the evidence that this species came from there is weak. Methods. We reviewed the evidence for the origin of O. corniculata using herbarium specimens, historic literature and archaeobotanical research. We also summarized ethnobotanical literature to understand where this species is most used by humans as a medicine. Results. Despite numerous claims that it is native to Europe there is no strong evidence that O. corniculata occurred in Europe before the 15 th century. Nor is there reliable evidence that it occurred in North or South America before the 19 th century. However, there is direct archaeobotanical evidence of it occurring in Southeast Asia at least 5000 years ago. There is also evidence from historic literature and archaeobotany that it reached Polynesia before European expeditions explored these islands. Examination of the traditional use of O. corniculata demonstrates that is most widely used as a medicine in southeast Asia, which, while circumstantial, also point to a long association with human culture in this area. Discussion. The most likely origin for O. corniculata is southeast Asia. This is consistent with a largely circum-Pacific distribution of section Corniculatae of Oxalis. Nevertheless, it is likely that O. corniculata spread to Europe and perhaps Polynesia before the advent of the modern era through trade routes at that time.