Proschismotherium is an extinct genus of ground sloth of the family Megalonychidae, endemic to Argentina during the Early Miocene. It lived from 17.5 mya — 16.3 mya, existing (as a genus) for approximately 1.2 million years. The type, and only, species, P. oppositum, was named in 1902 by Florentino Ameghino based on a single specimen found in the Santacrucian-aged of Argentina. Ameghino in 1902 placed Proschismotherium in the Megatheriidae, alongside Hapaloides, which was its sister taxon.