Stith Thompson was an American scholar of folklore. He is the "Thompson" of the Aarne-Thompson classification system. He attended Butler College and obtained his BA degree from University of Wisconsin. For the next two years he taught high school in Portland, Oregon, where he learned Norwegian. He earned his master's degree in English literature from University of California, Berkeley in 1912. He studied at Harvard University from 1912 to 1914; taught English at the University of Texas, Austin from 1914 to 1918; and obtained his Ph.D. from Harvard in 1919.
Thompson joined the English faculty of Indiana University (Bloomington), teaching composition. Interested in traditional ballads and tales, he organized summer institutes on the subject at the university that ran from the 1940s to the 1960s. These led, in 1962, to Thompson and another preeminent student of folklore, Richard Dorson, founding the University's Folklore Institute.
Thompson wrote, co-wrote, or translated numerous books and articles on folklore, and became arguably best known for his work on the classification of motifs in folk tales. His six-volume Motif-Index of Folk-Literature (1932-37) is considered the international key to traditional material.