The three species of chameleons inhabiting the primary forest on the western slope of Mount Kupe, Cameroon, Chamaeleo montium, Chamaeleo pfefferi, and Chamaeleo quadricornis, are compared with respect to elevational distribution, diet, and body size. Chameleo montium is restricted to lower elevations and markedly separated in elevational distribution from its congeners, which are exclusively found in the submontane forest. The three species prey almost entirely on arthropods, mostly coleopterans, heteropterans, hymenopterans, dipterans, and spiders; niche breadth values that incorpate prey availability are high and suggest opportunistic feeding. Niche overlaps are high with respect to prey type, but the smallest species, C. pfefferi, differs significantly from its congeners in terms of prey volume. Body size difference is largest between the two syntopic species, C. pfefferi and C. quadricornis, and identically low to the allotopic C. montium. The results on dietary segregation and morphological similarity are in accordance with competition limiting elevational distributions of the chameleons on Mount Kupe.