Richard Otto Maack (also Richard Karlovic Maak, Russian: Ричард Карлович Маак; 4 September 1825 – 25 November 1886) was a 19th-century Russian naturalist, geographer, and anthropologist. He is most known for his exploration of the Russian Far East and Siberia, particularly the Ussuri and Amur River valleys. He wrote some of the first scientific descriptions of the natural history of remote Siberia and collected many biological specimens, many of which were original type specimens of previously unknown species.