| Named By: | Andrew T. McDonald & John R. Horner in 2010 |
| Time Period: | Late Cretaceous, 74.6 Ma |
| Location: | USA, Montana - Two Medicine Formation |
| Size: | Unknown due to lack of remains |
| Diet: | Herbivore |
| Fossil(s): | Partial skull elements of two individuals |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischian | Ceratopsia | Ceratopsidae | Centrosaurinae | Pachyrhinosaurini | |
| Also known as: | | Styracosaurus ovatus | |
Rubeosaurus (meaning "bramble or thornbush lizard") is a genus of ceratopsian dinosaur which lived in what is now North America. Rubeosaurus fossils have been recovered from strata of the upper Two Medicine Formation of the Upper Cretaceous of Montana, dating to 74.6 million years ago.