中新马（学名Miohippus），是一属史前的马。牠们生存于始新世晚期至渐新世早期的北美洲。相信牠们是从渐新马中分支开来的，双方并且共存了达400-800万年之久。

渐新马于渐新世中期已完全消失，但中新马却变得更为大只。中新马重约40-55公斤。牠们比始新世的早期马祖先稍大，但仍比现今的马细小。

中新马的头颅骨比渐新马长。面沟更深及阔，脚踝关节完全不同。牠们的上臼齿有更多齿冠，有更多的磨擦面磨碎粗糙的食物。后来的马类物种都有着这种特征。

中新马有两个形态：一个适合森林的生活，而另一个则适合大草原生活。森林形态分支出了尖步马，其第二及第四脚趾较长，适合原始森林的地面。

Miohippus (meaning "small horse") was a genus of prehistoric horse existing longer than most Equidae. Miohippus lived in what is now North America during the Oligocene approximately 32-25 million years ago. While descending genera of this species lived during the Miocene period, Miohippus was a horse of the Oligocene. According to the Florida Museum of Natural History, Othniel Charles Marsh first believed Miohippus lived during the Miocene and thus named the genus using this incorrect conclusion. More recent research provides evidence that Miohippus actually lived during the Oligocene.