A Mountain Red-bellied Squirrel has an adult length of about 20 centimeters. Sexes are alike, with grayish brown upperparts and an auburn belly (fig.). It has strong claws, which are excellent for digging and ensure a firm grip on tree branches and trunks.

It has sharp vision an because of their location, its large, protruding eyes allow it to see behind, overhead and underneath without turning its head.