| Named By: | Edward Drinker Cope in 1874 |
| Time Period: | Late Cretaceous, 66 Ma |
| Location: | Canada, Alberta - Frenchman Formation. USA, Colorado - Laramie Formation |
| Size: | Uncertain due to lack of remains |
| Diet: | Herbivore |
| Fossil(s): | Fragmentary remains |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischia | Ornithopoda | Hadrosauridae | |
Cionodon (meaning 'column tooth') was a genus of dinosaur from the Late Cretaceous Period (Maastrichtian stage). The type species, Cionodon arctatus lived in what is now Colorado. It is classified as a hadrosaur, and was formally described by Edward Drinker Cope in 1874. It is a nomen dubium because it is based on very fragmentary remains. Two other species were described: Cionodon kysylkumensis from central Asia, and Cionodon stenopsis from what is now western Canada. Both are probably hadrosaurs, but are also fragmentary. Cionodon kysylkumensis has since been reclassified as Bactrosaurus kysylkumensis.