All species have soft, thick pelage that is either silky or woolly to the touch.
There is usually no contrast in color between the upper and lower parts. Females have only four mammae. Bunomys resembles Berylmys, and differs from Rattus, in that the interorbital and postorbital regions of the skull, as well as the dorsolateral sides of the braincase, are outlined only by low and inconspicuous ridges. From Berylmys, Bunomys differs in having a nontriangular cranial outline and orange incisor teeth. The mandibles of both genera are similar, but the coronoid process of Bunomys is larger relative to size of ramus.