Protoglyptodon is an extinct genus of glyptodont. It lived during the Late Miocene, and its fossilized remains were found in South America.
This animal, like all glyptodonts, had a dorsal armor protecting a large part of the body, consisting of well-fused polygonal osteoderms. The osteoderms were quite similar to those of Palaeohoplophorus, with a medium-sized, depressed central figure, and with wrinkled and irregular peripheral areas. Its carapace appearance was more irregular in Protoglyptodon. Its caudal tube bore osteoderms whose main figures were surrounded by a crown of perforations, but separated by peripheral areas decorated in a very irregular way.
Protoglyptodon primiformis was first described in 1885 by Florentino Ameghino, based on incomplete fossil remains coming from Late Miocene terrains of Argentina, first erroneously attributed to the Oligocene. Protoglyptodon was a member of the tribe Hoplophorini, a diverse and long-lived group of glyptodonts ; Protoglyptodon was closely related to the better known genus Palaehoplophorus.