U.S. ethnologist and champion of the rights of American Indians (American Indian) who wrote a book of general literary interest about his experiences as a student in a mission school in the 1860s. This memoir, The Middle Five (1900, new edition 1963), is rare in providing an account from an American Indian's viewpoint of his education by members of the majority culture.

His father—the son of a French trader and a woman of the Omaha tribe—chose the culture of his mother and became a chief. Believing that the Indians would have to come to terms with the white world, he sent his children to an English language school operated for Indians by the Presbyterians in Thurston County, Nebraska. Two of Francis La Flesche's sisters achieved prominence: Susette as a writer and activist for Indian causes, and Susan as a physician to the Omaha.

From 1881 to 1910 La Flesche was a clerk in the Bureau of Indian Affairs in Washington, D.C., meanwhile obtaining a law degree. He served as an ethnologist with the Bureau of American Ethnology from 1910 until his retirement in 1929. With Alice Cunningham Fletcher he wrote a study, The Omaha Tribe (1911). He also wrote two works, posthumously published, on the Osage: A Dictionary of the Osage Language (1932) and War Ceremony and Peace Ceremony of the Osage Indian (1938).