Roger Victor Emile Cayrel (born 4 December 1925, Bordeaux, France) is a French astronomer. His main interests are stellar atmospheres, galactic chemical evolution and metal-poor stars. He attended the Lycée Michel-Montaigne in Bordeaux and studied physics at the École normale supérieure and the Faculté des sciences de Paris. Beside his scientific work, he had a number of high-ranking posts in the management of science: director of the Canada-France-Hawaii Telescope (CFHT, 1974 1980), president of the IAU commission on stellar atmospheres (1973 1976) and head of the Bureau des Longitudes (1995 1996).