Roger Shaler Bagnall (born August 19, 1947 in Seattle) is an American classical scholar. He was a professor of classics and history at Columbia University from 1974 until 2007, when he took up the position of first Director of the Institute for the Study of the Ancient World (ISAW) at New York University.
Born in Seattle, Washington, Bagnall studied at Yale University (B.A., 1968) and University of Toronto (M.A., 1969; Ph.D., 1972). He has published several works on the history of Ancient Greece and Ancient Egypt, as well as papyrology. He was elected a Fellow of the American Academy of Arts and Sciences in 2000.