Recent molecular phylogenies of peramelemorphians suggest that thylacomyids (bilbies) and peramelids (modern bandicoots) diversified sometime in the late Oligocene or early Miocene. Until now, however, the earliest fossil evidence of thylacomyids and peramelids was from the Australian Pliocene. Here we describe the oldest peramelid and thylacomyid from the middle Miocene of the Riversleigh World Heritage Area, northwestern Queensland. The peramelid, Crash bandicoot, gen. et sp. nov., is represented by a single maxilla containing M1–3 that exhibits peramelid synapomorphies, including development of a metaconular hypocone, an incomplete centrocrista, and well-developed anterior cingulum. The thylacomyid, Liyamayi dayi, gen. et sp. nov., is represented by M2 and m1, which show thylacomyid synapomorphies including a conical entoconid, a conical stylar cusp B (StB) and StD, and reduced distance between the metastyle and StD. The results of our phylogenetic analysis indicate that both species are part of crown-group Peramelemorphia