| Named By: | X. Zhao, Z. Cheng & X. Xu in 1999 |
| Time Period: | Late Jurassic, 148 Ma |
| Location: | China, Liaoning - Tuchengzi Formation |
| Size: | Uncertain due to lack of fossils, but roughly estimated to be about 1 meter long |
| Diet: | Herbivore |
| Fossil(s): | Partial skull, jaw, cervical (neck) vertebrae, partial scapula (shoulder blade), and partial humerus (upper arm bone) |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischia | Marginocephalia | Ceratopsia | Chaoyangsauridae | |
| Also known as: | | Chaoyangosaurus | Chaoyoungosaurus | |
Chaoyangsaurus ("Chaoyang lizard") was a marginocephalian dinosaur from the Late Jurassic of China (dated to between 150.8 and 145.5 million years ago). Chaoyangsaurus belonged to the Ceratopsia (Greek for "horned faces"), Chaoyangsaurus, like all ceratopsians, was primarily a herbivore.