| Named By: | Efremov in 1938 |
| Time Period: | Late Permian |
| Location: | Russia - Krasnoshchel' Formation |
| Size: | Holotype roughly about 37-38 centimetres long |
| Diet: | Carnivore |
| Fossil(s): | Almost complete |
| Classification: | | Chordata | Synapsida | Eupelycosauria | Varanopidae | Mycterosaurinae | |
Mesenosaurus is an extinct genus of non-mammalian synapsid. The only know species within this genus is Mesenosaurus romeri.