Closely related to Triceratops, Regaliceratops was named for its plated frill, which its describers thought looked somewhat like a crown. In 2005, geologist Peter Hews discovered a skull at the Oldman River in Alberta. The fossil was secured by a team of the Royal Tyrrell Museum. The specimen was given the nickname "Hellboy" for its horns and the difficulty of removing it from the matrix.
In 2015, Caleb Marshall Brown and Donald Henderson named and described the type species Regaliceratops peterhewsi. The generic name combines Latin regalis, "royal", a reference to both the crown-shaped neck shield and the "Royal" Tyrrell, with a Greek keras, "horn", and ops, "face". The specific name honours Hews.
The holotype, TMP 2005.055.0001, was found in a layer of the St. Mary River Formation dating from the middle Maastrichtian, about 68 million years old. It consists of a rather complete skull of which the snout bone, the rostral, is lacking. The skull has been deformed by compression and its rear and underside are obscured by matrix.
Regaliceratops was about five metres long, with an estimated weight of 1.5 tonnes.