Robert Michael "Bob" Sullivan (born August 4, 1951) is a vertebrate paleontologist, noted for his work on fossil lizards and dinosaurs. Sullivan discovered the second and most complete skull of the hadrosaurid dinosaur, Parasaurophus tubicen, and skulls of the ankylosaurids Nodocephalosaurus kirtlandensis and Ziapelta sanjuanensis. He also made contributions to Late Cretaceous vertebrate faunas from the San Juan Basin, New Mexico, including establishing the Kirtlandian land vertebrate "age" for a time interval between the Judithian and younger Edmontonian "ages."