Microcebus griseorufus has a pelage color that is alternating light neutral gray, pale neutral gray, and light pale neutral gray dorsally and ventrally light grayish-white on the anterior two-thirds and bicolored light grayish-white and pale neutral gray on the posterior one-third. It has a cinnamon colored dorsal stripe running from the crown of the head or the shoulders to the end of the tail. The head of this species has a pale neutral gray spot above the nose, cinnamon around the eyes, a clay colored crown, and ears that are light neutral gray. The dorsal side of the tail is cinnamon colored while the ventral side is grayish-beige on the most distal two-thirds and cinnamon with faint brownish black streaks on the proximal one-third. The hands and feet are colored grayish-white and the vibrissae are dark in color. This species has a relatively robust skull. The size of the reddish-gray brown mouse lemur ranges from , while their mass can range between . It is assumed that like other nocturnal species, the reddish-gray mouse lemur has very sensitive ears, making them important for communication, social encounters, predator avoidance, and critter finding.
