Synthetoceratinae is an extinct subfamily of Protoceratidae, deer-like herbivorous mammals belonging to the order Artiodactyla. They were endemic to North America during the Miocene epoch, living 23.03—3.9 Ma, existing for approximately 19.13 million years.[1][failed verification]
Synthetoceratinae was named by Frick (1937). Its type genus is Synthetoceras. It was considered monophyletic by Webb et al. (2003). It was assigned to Protoceratidae by Webb (1981), Prothero (1998),[2] Webb et al. (2003),[3] Hulbert and Whitmore (2006)[4] and Prothero and Ludtke (2007).[5]