This species ranges from the Juba River in southern Somalia, southwards along the East African coast to the Ruvuma River, Tanzania, and inland from here to the Kenya highlands. The southernmost locality is Milo on the northern end of Lake Malawi. This species is present on Zanzibar, Pemba and Mafia Islands, Tanzania. It may be present in Mozambique, but there are no confirmed records. There is also no indication that the species occurs in Malawi (Ansell and Dowsett 1988). Recorded up to 2,500 m (Olson 1979). Sympatric with Galagoides zanzibaricus, Galagoides cocos, Galago senegalensis, Galagoides granti and Otolemur crassicaudatus (T. Butynski and Y. de Jong pers. comm.).

There are four subspecies: O. g. garnettii appears to be restricted to Zanzibar, Pemba and Mafia Islands; O. g. panganiensis is present in Tanzania from the Mozambique border in the south to Tanga, Mount Kilimanjaro and Lake Manyara in the north; O. g. lasiotis ranges northwards from Tanga in Tanzania, along the Kenyan coastline to the Juba River in Somalia; it is also present in the Taita Hills and Kibwezi (north of Mount Kilimanjaro); and the subspecies O. g. kikuyuensis is restricted to the Kenyan highlands east of the Rift Valley (Nairobi, Aberdares and Mt Kenya).