Citizens’ political engagement is widely regarded as vital for democracy. In Africa, however, the assumption has often been that citizens do not engage robustly in many activities such as campaigning or attending community meetings, with political participation primarily limited to voting. Thus, little research explores the drivers of these other vital activities. We aim to fill the gap, using an original survey experiment to explore the drivers of citizen participation in Zambia around the 2021 national elections. Contrary to widely held views in the literature, we find that partisanship is a critical driver of participation, with social incentives and ethnicity also playing important but less significant roles. Finally, we seek to understand the mechanisms underpinning these results, finding that citizens anticipate sanctions if they fail to support a co-partisan but not a co-ethnic candidate. These findings have important implications for understanding political engagement and democratic development throughout the region.