Orodromeus was by Horner & Weishampel assigned to the Hypsilophodontidae, as the youngest known member.
Today these are seen as an unnatural, paraphyletic, group, and Orodromeus is simply considered to be a basal member of the Euornithopoda.

Brown et al. (
2013) put it in the family Thescelosauridae and named a new subfamily (Orodrominae) after it.
Orodromeus was by Horner & Weishampel assigned to the Hypsilophodontidae, as the youngest known member. Today these are seen as an unnatural, paraphyletic, group, and Orodromeus is simply considered to be a basal member of the Euornithopoda.
Brown et al. (2013) put it in the family Thescelosauridae and named a new subfamily (Orodrominae) after it.
Orodromeus