Maurice Kottelat (born 16 July 1957 in Delémont, Switzerland) is a Swiss ichthyologist specializing in Eurasian freshwater fishes.
Kottelat obtained a License in Sciences at the University of Neuchâtel in 1987 and in 1989 a doctoral degree from the University of Amsterdam. In 1980 he went to Thailand where he began his field research on Southeast Asian and Indonesian fresh water fishes. In 1997 he wrote an important revision on the genus Coregonus, which includes the fish species from Lake Geneva, Lake Constance and other lakes in Switzerland. Together with Dr. Tan Heok Hui he worked in Sumatra, where they discovered Paedocypris progenetica, which is considered the smallest fish in the world. In 2007 he published a Handbook of European Freshwater Fishes together with Jörg Freyhof. Kottelat has described more than 440 fish species new to science.
In 2006 he was awarded a Doctor Honoris Causa degree at the University of Neuchâtel. Kottelat is the former (1997-2007) and present (2012-present) president of the European Ichthyological Society. He is a commissioner of the International Commission on Zoological Nomenclature. For most of his career, he has held no academic position but worked as a "freelance taxonomist".