This paper investigates the determinants of opposition party fragmentation in the developing
democracies of Africa. Rater than attribute fragmentation to ethnic diversity or to
formal political institutions, I argue that informal institutions, namely the strength of traditional
chiefs, explains fragmentation in opposition movements. When chiefs are strong, they are
incentivize consolidation in opposition movements. Using Afrobarometer survey data and
electoral returns, I test the relationship between chiefs and opposition fragmentation across
a sample of 18 sub-Saharan African countries. I find that, in line with my hypothesis, chief
strength is related to lower levels of opposition party fragmentation. This approach can account
for why, despite similar electoral institutions and levels of ethnic diversity, we see different
levels of opposition party fragmentation in different African countries. The paper should be of
interest to scholars of African politics, informal institutions, and party systems.