Styracosaurus was ceratopsid (horned) dinosaur. Of moderate size at about 6 m (19.5 ft.) long and several tonnes in weight, it resembled the modern rhinoceros in general appearance. Like other horned dinosaurs, Styracosaurus did not hold its forelimbs directly beneath its body. Its jaws were adapted to chop rather than grind the plants that were its food.

There is only one species of this well known dinosaur: Styracosaurus albertensis. Styracosaurus is easily recognized by the large, elongated and spiked frill at the back of its skull, and the long horn at the top of its nose. Canadian palaeontologist Lawrence Lambe named Styracosaurus in 1913 for the similarity of the frill-spikes to that of the spike (in Greek: styrax) at the base of ancient Greek spear shafts. The species name, albertensis, refers to the fact that it was found in Alberta.

This ceratopsid is known only from 76 million-year-old Late Cretaceous rocks of Dinosaur Provincial Park. There, a few articulated specimens have been discovered, along with concentrations of tumbled Styracosaurus bones accumulated in what is called a bonebed.

This bonebed indicates that many Styracosaurus died at one time in a mass mortality event. The reason for this event is unclear. It has been suggested that Styracosaurus, like many other horned dinosaurs, congregated in large herds, and one such herd may have been the victim of a huge storm flood.