The northern greater galago has a head-and-body length of 23–34 cm (26 cm average), a tail length of 31–44 cm (average 36 cm) and body weight of 0.5–1 kg (mean 0.75 kg). This species exhibits significant degree of sexual size dimorphism with males larger than the females. This is due to bimaturism, where males have a longer period of growth and have an average 19% greater body mass than females. The average male is 794 g and the average adult female is 734 g.