Thordar Fladmoe Quelprud (September 2, 1901 – May 16, 1992) was a Norwegian geneticist. Quelprud was a student of Kristine Bonnevie, who established the Institute for Genetic Research (Norwegian: Institut for Arvelighetsforskning) in 1916. Bonnevie sent him to Berlin in the 1920s, where he became fascinated with German scientific racism. He was appointed a professor of genetic studies at the University of Oslo during the Second World War, and he was removed from the position in 1945.