Mionothropus is an extinct genus of nothrotheriine nothrotheriid sloth which existed in Peru in western Amazonia, during the late Miocene (Huayquerian age). It is known from the holotype LACM 4609/117533, which includes cranial remains, recovered from the riverbank deposits of the Río Acre region, were originally assigned to Nothropus priscus. It was first named by Gerardo De Iuliis, Timothy J. Gaudin and Matthew J. Vicars in 2011 and the type species is Mionothropus cartellei.