Dysganus (dis-GANN-us) is a dubious genus of ceratopsian dinosaur from the Campanian stage of the Late Cretaceous. The fossil teeth referred to Dysganus were first collected by Charles Sternberg from the Judith River Formation of Montana and later described by Edward Drinker Cope. All of the species are now seen as dubious ceratopsians, though referred material from tyrannosaurids and hadrosaurids were found in New Mexico.