The four-horned chameleon is found only in some highland areas associated with the Cameroon line across Cameroon and eastern Nigeria; its range includes the Western High Plateau, the Bamboutos massif, Mount Manengouba, Oku Massif, the Bakossi Mountains including Mount Kupe, and the Obudu Plateau in Nigeria. T. q. eisentrauti in particular is endemic to the Rumpi Hills of Cameroon. Overall, T. quadricornis has an extent of occurrence of 13,300 km2 and an inferred area of occupancy of 1,000 km2. The species is primarily associated with relatively intact montane forest with limited human activity, where it has a relatively restricted elevational range (1150 to 2400 metres). Research suggests that this is likely to reflect competition with other chameleon species rather than physiological tolerances. The type locality for the species is Mount Manegouba in Cameroon.