Oryctodromeus (meaning "digging runner") was a genus of small ornithopod dinosaur, the fossilized remains of which have been found in rocks dating from the middle Cretaceous Blackleaf Formation of southwestern Montana (Cenomanian stage), roughly 95 million years ago. A member of the small, presumably fast-running herbivorous family Hypsilophodontidae, Oryctodromeus is the first dinosaur published that shows evidence of burrowing behavior.