Gotthilf Hempel (born March 8, 1929) is a retired German marine biologist and oceanographer.
Hempel studied biology and geology at the universities of Mainz and Heidelberg. In 1952 he gained his Ph.D. with a study on the energetics of grasshopper jumps from Heidelberg University. He then went on to work as a scientific assistant at various research institutes in Wilhelmshaven, Helgoland, and Hamburg, where he habilitated with a thesis on the ecology of fry in 1963. Four years later, he became a professor at the University of Kiel at the Institute of Oceanography, where he remained director for the next 14 years. In 1981, he helped found the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven whereupon he became the institution's first director. In the same year, he also became director of the Institute for Polar Ecology at the University of Kiel. In Bremerhaven, he initiated the construction of the polar research vessel PFS Polarstern. In 1992, he became the first director of the then newly founded Center for Marine Tropical Ecology at the University of Bremen. Hempel retired in 1994.
He has been interested and active in research politics throughout his career. From 1963 to 1967 he worked for UNESCO and the FAO and from 1990 to 1996 he was a member of the Wissenschaftsrat, the scientific advisory committee of Germany. He has been and is an active proponent of scientific collaboration and education initiatives in underdeveloped countries, and has advocated a more sustainable exploitation of natural resources. Hempel is the editor of the journal Polar Biology, and he has also published several books. He has had more than 70 doctoral candidates, notably Daniel Pauly. From his time spent researching oceanological topics he has managed to spend over 1000 days aboard research vessels.