| Named By: | John Willis Stovall in 1937 |
| Time Period: | Kungurian, 279.5-272 Ma |
| Location: | USA, Oklahoma, Texas |
| Size: | 6 meters long |
| Diet: | unavailable |
| Fossil(s): | Many individuals are known |
| Classification: | | Chordata | Synapsida | Pelycosauria | Caseasauria | Caseidae | |
Cotylorhynchus was a very large synapsid that lived in the southern part of what is now North America during the Early Permian period. It is the best known member of the synapsid clade Caseidae, usually considered the largest terrestrial vertebrates of the Early Permian, though they were possibly aquatic.