Guy Graham Musser (August 10, 1936 – October 2019) was an American zoologist. His main research is in the field of the rodent subfamily Murinae, in which he has described many new species. Musser was born in Salt Lake City, Utah. He attended elementary and secondary public schools until 1955 and in 1967 obtained a PhD at the University of Michigan with a thesis about the taxonomy of the Mexican gray squirrel (Sciurus aureogaster). In 1966 he joined the American Museum of Natural History where he became curator of mammals. Since his retirement in 2002 he is curator emeritus.