This paper describes a new tree-kangaroo of the extinct genus Bohra (B. illuminata sp. nov.). Its remains were collected from a diverse middle Pleistocene fauna preserved in caves recently discovered beneath the Nullarbor Plain of south-central Australia. The adult holotype and juvenile paratype are represented by associated cranial and postcranial material. They confirm that two previously known species, B. paulae and B. wilkinsonorum, which were described on the basis of disparate parts of the skeleton, are congeneric. While Bohra is closest in morphology to the extant tree-kangaroo genus Dendrolagus, it shares several similarities with Petrogale (rock-wallabies). This is consistent with recent molecular studies that suggest that tree-kangaroos and rock-wallabies share a common ancestry.