| Named By: | M. F. Ivakhnenko in 2000 |
| Time Period: | middle Permian |
| Location: | Russia |
| Size: | Skulls about 5 centimetres long |
| Diet: | Insectivore |
| Fossil(s): | Skull |
| Classification: | | Chordata | Synapsoda | Therapsida | |
Nikkasaurus is an extinct genus of therapsid. They were small animals, with skulls about 5 cm long. Their eyes had large orbits and sclerotic rings. The head was tilted back, as with all therapsids. The skull looks superficially similar to those of the Pelycosaurs, in particular Varanopidae. Nikkasaurus was probably mainly insectivorous, and possibly nocturnal. The only known species is N. tatarinovi, described by MF Ivahnenko in 2000, from the Middle Permian Mezen River Basin. The family Nikkasauridae also includes the Reiszia genus with two species (R. gubini and R. tippula) described by Ivahnenko in 2000 from the same sediment. Nikkasaurus is possibly a relic of a more ancient stage of therapsid development.