In this article, we explore the reasons why some ethnic groups tend to vote along ethnic lines while others do not. We argue that existing explanations for ethnic voting can be grouped into three main approaches: policy-based, grievance-based, and clientelism. However, we contend that inconsistencies in previous empirical research come from a failure to account for the political context in which ethnic voting occurs. Specifically, we argue that ethnic voting in democracies operates on a different logic than in non-democratic regimes. Our argument posits that policy- and grievance-based factors are the primary determinants of ethnic voting in democracies, whereas clientelist networks play a crucial role in understanding ethnic voting in autocratic regimes. To test our hypotheses, we use a sample of 428 ethnic groups from 33 African countries between 2005 and 2018, as well as a novel survey-based measurement of voting preferences among ethnic group members. Our findings support our hypotheses: in democratic regimes, grievance-based and policy-based explanations have strong explanatory power, whereas clientelism is the primary driver of ethnic bloc voting in autocracies. We conclude that both regime type and the different underlying mechanisms of clientelism require greater consideration in the research on ethnic voting.