Political party systems are an important element of political systems in Africa and elsewhere. They form the central intermediate institution between the general population and the government. Party systems represent and aggregate diverse political views and group interests, and they form coalitions that then form governments with potentially important consequences of democracy and political stability. Unlike the case in the period directly after independence, African party systems have been overwhelmingly multiparty since the 1990s. As a result, the literature has grown significantly, although most works focus on political parties rather than party systems. Many efforts have been devoted to classification, referring to the legal context as well as, more specifically, the number of relevant parties, the levels of institutionalization, and, less often, the degree of ideological or other polarization. While levels of institutionalization and ideological differences are generally not pronounced, more than half of African party systems have been one-party dominant, of which most are authoritarian. In contrast, two-party and pluralist-party systems, which make up approximately one half of all multiparty systems, are generally more democratic. Besides determining classifications, most analytical work focuses on the determinants of African party systems using quantitative and qualitative as well as macro- and micro-level methodologies. Three determinants are debated: first, ethnicity, which has been cited as the main social cleavage behind African party systems; however, while ethnicity matters, its effects vary and are limited; second, political institutions, especially electoral systems for legislative elections, which only partly explain fragmentation or other features; third, the performance of political parties and rationalist approaches. Scholars largely agree that all of these elements need to be taken into account. While certain functions of party systems may facilitate democratization and political stability or other outcomes, little empirical work exists on the consequences of party systems. Some evidence suggests that highly institutionalized, moderately fragmented, and polarized systems promote democracy. Future research faces many challenges, in particular the development of integrated theory and more fine-grained data, as well as an increased focus on the consequences of party systems.