Dieter Carl Wasshausen (born 15 April 1938 in Jena, Germany) is an American botanist specialized in Spermatophytes. In 1962 he started working at the Smithsonian Institution as a technician. In 1976 he became chairman of the Botany Department, a post he held until 1982 He studied at the George Washington University receiving a PhD in 1972. Wasshausen has described approximately 247 new species in various families, and five new species have been named for him. The standard author abbreviation Wassh. is used to indicate this person as the author when citing a botanical name.