Norman I. Platnick (born 1951 in Bluefield, West Virginia) is an American arachnologist. He is a Professor Emeritus of the Richard Gilder Graduate School and Peter J. Solomon Family Curator Emeritus of the invertebrate zoology department of the American Museum of Natural History. A 1973 Ph.D. recipient at Harvard University, Platnick has described over 1,800 species of spiders from around the world, making him the second most prolific arachnologist in history, behind only Eugène Simon. Until 2014 he was also the maintainer of the World Spider Catalog, a website formerly hosted by the AMNH which tracks the arachnology literature, and attempts to maintain a comprehensive list, sorted taxonomically, of every species of spider which has been formally described. In 2007 he received the International Society of Arachnology's Bonnet award, named for Pierre Bonnet, in recognition for his work on the catalog.
Platnick is recognized as a world leader in spider taxonomy. Dr. Quentin D. Wheeler stated "He is the best arachnologist of his generation, has published more monographs and nomenclatural contributions than anyone, period."