Frederick Kroeber Sparrow (11 May 1903–October 2, 1977) was an American mycologist. He was known for his research on aquatic fungi, and in particular the genus Physoderma, and he produced a well-received monograph in 1943 titled The Aquatic Phycomycetes Exclusive of the Saprolegniacea and Pythium; this was republished in 1960 as Aquatic Phycomycetes.
Born in Washington, D.C., the only child of Minnie Tomlinson and Frederick Kroeber, Sparrow attended local schools and developed an early interest in science. It was during these years he met Jack Faber, who later became a microbiologist and lacrosse coach. Sparrow earned his undergraduate degree from the University of Michigan in 1925, and entered Harvard University as a graduate student that year. He obtained a master's degree in 1926 and his PhD from this institution three years later.
Sparrow served under various positions for the Mycological Society of America, including Secretary-Treasurer from 1945–1948, Vice-President in 1948, and President in 1949. He was also the President of the Michigan Academy of Arts, Sciences, and Letters in 1954.
Sparrow was awarded the Award of Merit by the Botanical Society of America in 1968, the same year he was elected a Fellow of the American Association for the Advancement of Science. Sparrow died in Ann Arbor, Michigan, in 1977.