Nonmammalian vertebrate fossils are common in Late Cretaceous (Cenomanian-Maastrichtian) rocks throughout Wyoming. Strata of this age, spanning 35 million years (65–100 million years ago) and reaching thicknesses of 3,000 meters, flank many of the major structural basins within the state. Comprehensive faunal lists are compiled for the Late Cretaceous of Wyoming. Vertebrate fossils of this age have been known in the state since 1872. The faunas of the latest Cretaceous (Maastrichtian), nonmarine Lance and “Mesaverde” formations are the best known and most diverse within the state. Late Cretaceous nonmammalian vertebrate fossils found in Wyoming consist of remains of sharks, rays, bony fishes, frogs, salamanders, champsosaurs, turtles, lizards, mosasaurs, snakes, alligators, crocodiles, pterosaurs, dinosaurs, plesiosaurs, ichthyosaurs, and birds. These organisms were inhabiting the subtropical to warm temperate, marine, transitional marine, or nonmarine coastal floodplain and upland environments associated with the transgressions and regressions of the Late Cretaceous epicontinental seaway. Turonian-Coniacian age localities in western Wyoming are some of the earliest known occurrences of nonmarine organisms along the western coast of this seaway. Nodosaurid ankylosaur material from one of these localities represents some of the earliest Late Cretaceous dinosaur fossils known in North America. Continued research on Late Cretaceous faunas from Wyoming will add greatly to the understanding of the biota of the Western Interior during the end of the Mesozoic.