Horizontal inequalities (HIs) within a country, or inequalities among groups, have been shown to be an important source of violent conflict. Relevant group categorizations include religion, ethnicity, and region. HIs can also be measured in different ways. Ethnicity, language, religion, race, and region are examples of potentially relevant and salient group categorizations. In this paper the authors will review the prevailing HIs and their management in four West African countries - Cote d’Ivoire, Ghana, Mali, and Nigeria. The report provides some basic facts about these four countries, which vary greatly in area, per capita income, poverty, child mortality rates, and other features. In terms of ethnoreligious demography, it is important to note that all four countries have a highly diverse ethnic population, and three of the four (Ghana, Nigeria, and Cote d’Ivoire) have substantial Christian and Muslim populations. Each of the case study countries has had a relatively turbulent and complex political history in recent decades. The four case study countries present instructive examples of the possible (mis)management of HIs. In this paper the authors analyze the evolution and management of the prevailing HIs in each of the four cases. Section one gives introduction. Section two presents evidence on the evolution and current state of HIs in each country. Section three analyzes the main causes of the prevailing HIs, while section four focuses on the governments’ attitudes, policies, and measures toward HIs. Section five discusses the links between the HIs observed and the political outcomes. Section six draws some conclusions and makes policy recommendations for improved management of HIs in multiethnic developing countries generally, and specifically in four case study countries.