This chapter examines the intricate relationship between ethnicity and decentralisation and their potential impact on constitutionalism. As a result of the way colonisation was undertaken, the population of most African states is multi-ethnic. The intrusion of ethnicity into politics and the economy has fundamentally defined Africa’s systems of government. Ultimately, ethnic politics has been deeply divisive and has had a major, and mostly negative, impact on constitutionalism. The chapter then suggests two motives behind decentralisation: to diffuse the tensions that arise in a unitary state with a multi-ethnic population; and to promote the values of constitutionalism, of which the former is the more common. However, this does not mean ethnically motivated decentralisation may not promote constitutionalism. The basic idea behind decentralisation is to limit in some ways the powers and functions of the central government by transference to sub-national governments.