The Mentawai three-striped squirrel is restricted to the Mentawai Islands west of Sumatra. Its dark back has faint stripes, and it eats seeds, fallen fruit, and arthropods.
Its dark dorsal fur has faint stripes, while the underside is dark gray without buff coloration. The muzzle is relatively long; coat and tail colors differ among subspecies.
It is described as diurnal and terrestrial, eating seeds, fallen fruit, and arthropods. Its nests are in burrows or fallen trees.
An extinction-risk assessment has not been added yet.