The generic name is derived from mojo and the specific name means "conspicuous pride" in Greek, both referring to the skull frill. The species is based on fossils thought by other researchers to belong to Chasmosaurus. The species Chasmosaurus kaiseni, known from specimen AMNH 5401, a nearly complete (but partially restored) skull on display at the American Museum of Natural History, was considered to share features in common with Mojoceratops perifania and therefore was considered a possible synonym. However, the parietal (back margin of the frill) is not preserved, and was restored with plaster based on specimens of Chasmosaurus, which caused confusion among scientists in previous decades, because the parietal bone is critical for determining differences between species in ceratopsids like Chasmosaurus and Mojoceratops. Chasmosaurus kaiseni was then by Longrich regarded as a nomen dubium, rather than as the senior synonym of M. perifania. Longrich also regarded the holotype of Eoceratops as probably being an exemplar of Mojoceratops. He considered it too poorly preserved for a reliable determination, especially as it belonged to a juvenile individual, and regarded it too as a nomen dubium, rather than as the senior synonym of M. perifania. A 2016 overview of Chasmosaurus found C. kaiseni and Eoceratops to be referable to Chasmosaurus sp. due to the lack of the parietal preserved in the holotypes of both. Following the original assignment of the holotype and other skulls to Mojoceratops, several teams of researchers published work questioning the validity of this new genus. In 2011, Maidment & Barrett failed to confirm the presence of any supposedly unique features, and argued that Mojoceratops perifania was a synonym of Chasmosaurus russelli. Campbell and colleagues, in their 2016 analysis of Chasmosaurus specimens, agreed with the conclusions of Maidment & Barrett, adding that some supposedly unique features, such as grooves on the parietal bone, were actually also present in the holotype of C. russelli and, to various degrees, in other Chasmosaurus specimens. This variability, they argued, strongly suggested that Mojoceratops was simply a mature growth stage of C. russelli. Recently, the referral of Eoceratops, C. kaiseni, and Mojoceratops to C. russelli was considered doubtful as the holotype of C. russelli is actually from the upper Dinosaur Park Formation, according to recent fieldwork. This situation is further complicated since C. russelli may not even belong to the genus Chasmosaurus, sharing features with the contemporaneous derived chasmosaurine Utahceratops. Today, taxonomy of Chasmosaurus