William D. Turnbull (1922-2011) was an American paleontologist, associated with the Chicago Field Museum. His special interest in mammals saw him publish over a hundred papers, continuing after his retirement as curator of mammals at the Museum. He undertook field work in Australia, searching for evidence of recently extinct species, and frequently made expeditions to sites at the Washakie Formation in southwest Wyoming. Special credit is given to his studies in the paleontology and biogeography of dinosaurs and Eocene mammals.
A species of marsupial in the Thylacinidae family, an ancestor of the Tasmanian tiger Thylacinus cynocephalus, was named as Badjcinus turnbulli in honour of his contributions to Australian palaeontology.