Bagaceratops (meaning "small-horned face") is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 72 to 71 million years ago.

Although emerging late in the reign of the dinosaurs, Bagaceratops had a fairly primitive anatomy—when compared to the much derived ceratopsids—and kept the small body size that characterized early ceratopsians.

During the large field work of the Polish-Mongolian Palaeontological Expeditions in the 1970s, abundant protoceratopsid specimens were discovered on eroded surfaces of the Hermiin Tsav locality of the Barun Goyot Formation, Gobi Desert.

[1] In 1993, the Japan-Mongolia Joint Paleontological Expedition collected an articulated and nearly complete Bagaceratops skeleton (MPC-D 100/535) from the Barun Goyot Formation at the Hermiin Tsav locality.

The holotype of Magnirostris, IVPP V12513, represents a nearly complete skull lacking the frill region of a large individual and was collected during expeditions led by the Sino-Canadian Dinosaur Project.

[10] In 2006 Mackoviky regarded all of these ceratopsians as junior synonyms of Bagaceratops based on the reasoning that all exhibit anatomical traits already seen on other specimens of this protoceratopsid, and some of them are likely products of preservation.

Czepiński reexamined many of the specimens originally described by Maryańska and Osmólska, as well as the respective holotypes of these taxa, providing evidence that all traits used to separate them are, in fact, indistinguishably present on Bagaceratops and they fall within the large intraspecific variation of this taxon.

He also considered Breviceratops to be a distinct and separate genus of protoceratopsid, from both Bagaceratops and Protoceratops, as it features a combination of basal (primitive) and derived (advanced) traits.

[1][13] Bagaceratops belonged to Ceratopsia, a group of herbivorous dinosaurs with parrot-like beaks which thrived in North America and Asia during the Cretaceous Period, which ended roughly 66 million years ago.

[17][18][16] Bagaceratops is the most common taxon across the Barun Goyot Formation,[1][13] which was also home to many other vertebrates, including the ankylosaurids Saichania, Tarchia and Zaraapelta;[19][20] alvarezsaurids Khulsanurus and Parvicursor;[21] birds Gobipipus, Gobipteryx and Hollanda;[22] fellow protoceratopsid Breviceratops;[13] dromaeosaurids Kuru and Shri;[23][24] halszkaraptorine Hulsanpes;[25] pachycephalosaurid Tylocephale;[26] and oviraptorids Conchoraptor, Heyuannia and Nemegtomaia.

[33][34] This formation has produced numerous dinosaurs, such as closely related protoceratopsid Protoceratops;[35] ankylosaurid Pinacosaurus;[36][37] alvarezsaurid Linhenykus;[38] dromaeosaurids Linheraptor and Velociraptor;[39][40] oviraptorids Machairasaurus and Wulatelong;[41][42] and troodontids Linhevenator, Papiliovenator, and Philovenator.