巨犀类（学名Indricotheriinae）是跑犀科下巨犀亚科的犀牛。牠们的四肢很长，没有角。牠们自始新世开始演化至中新世早期。初期出现的跑犀科是很轻盈及跑得很快的动物，与现今的犀牛相距甚远。到了始新世晚期及渐新世初期，巨犀类开始出现，很快就变得很巨型。牠们分布在现今中国西南部、哈萨克斯坦及巴基斯坦，栖息在海边的雨林。

巨犀类于渐新世中期至中新世早期到达了演化的颠峰，变成了真正巨型动物，包括巨犀属及副巨犀属。牠们是陆地上最大的哺乳动物，约有中等蜥臀目恐龙的身型。牠们只限于在亚洲中部生活，当时亚洲中部为大片的低地。与印度次大陆撞击及喜玛拉雅山的隆升引起了全球寒冷化、沙漠化及森林的消失，令这种巨型有蹄类灭绝。另外，在蒙古及俄罗斯也有发现一些未确认的巨犀类物种。

Indricotheriinae is a subfamily of Hyracodontidae, a group of long-limbed, hornless rhinoceroses convergently similar to the sauropod dinosaurs that evolved in the Eocene epoch and continued through to the early Miocene. The earlier hyracodontid species, such as Hyracodon were modest-sized, fast-running, lightly built animals with little similarity to modern rhinos. However, during the late Eocene and early Oligocene, the indricotherines evolved, and quickly grew to huge sizes. They flourished in the rainforests of a coastal region that became Kazakhstan, Pakistan, and southwest China, and lived further inland throughout central Asia as well.