Palaeosyops (Greek: "old" (paleos), "boar" (kapros), "face" (ops)[1]) is a genus of small brontothere which lived during the early to middle Eocene.

[2] It was about the size of small cattle, with a weight of 600–800 kg depending on the species.

P. major was the largest species, reaching the size of a small cow.

Its describer, Joseph Leidy, erroneously thought that Palaeosyops consumed both plants and animals after examining the fang-like canines.

However, it is now known that all brontotheres were strict herbivores, and that many, if not most genera of hornless brontotheres had fang-like canines, possibly for both defense from predators, and intraspecific competition.