Thescelosaurus (name meaning ''Wonderful Lizard'') is a genus of ornithischian dinosaur that lived during the Late Cretaceous period in western North America.
In the Series 2 finale, "Death of a Dynasty II: The Return of the King", a flock of Thescelosaurus were brought to the park from Late Cretaceous Montana 65 million years ago. They reside in the Ostrich Paddock Enclosure and recently welcomed some hatchlings into the flock.