The Brazilian arboreal mouse, Rhagomys rufescens, is a South American rodent species of the family Cricetidae. It is found in the Atlantic Forest of southeast Brazil, often close to bamboo thickets. It can be distinguished from Rhagomys longilingua, the only other species in its genus, by the absence of spines among the hair. Formerly believed to be extinct after no sightings were recorded for over 100 years, the species has since been found in four localities. However, it is nowhere common, and all of these are forest fragments, and ongoing deforestation threatens the species' survival. For these reasons, the International Union for Conservation of Nature has assessed its conservation status as being "near-threatened".