Timothy Plowman (November 17, 1944 – January 7, 1989) was an ethnobotanist best known for his intensive work over the course of 15 years on the genus Erythroxylum in general, and the cultivated coca species in particular. He collected more than 700 specimens from South America, housed in the collection of the Field Museum of Natural History.
Plowman joined the Field Museum of Natural History in 1978 where he became tenured in 1983 and was appointed Curator in 1988. He published more than 80 scientific papers (46 on Erythroxylum) and served as editor for several scientific journals.
He is one of the main subjects of One River: Explorations and Discoveries in the Amazon Rain Forest by Wade Davis.  Both were students of Richard Evans Schultes, the father of modern ethnobotany.