| Named By: | Samuel Wendell Williston in 1915 |
| Time Period: | Early Permian |
| Location: | USA, Colorado - Waggoner Ranch Formation, Oklahoma - Cutler Formation and Texas - Garber Formation |
| Size: | About 60 centimetres long |
| Diet: | Carnivore/Insectivore |
| Fossil(s): | Several individuals |
| Classification: | | Chordata | Reptilia | Synapsida | Pelycosauria | Varanopidae | |
| Also known as: | | Basicranodon | Eumatthevia | |
Mycterosaurus was an extinct genus of synapsid belonging to the family Varanopidae. It is classified in the varanopid subfamily Mycterosaurinae. Mycterosaurus is the most primitive member of its family. It lacks some features that its advanced relatives have. Mycterosaurus was about 60 cm long.