This study examines the relationship between the slave trade and the fiscal capacity of African countries. Using country-level data, we find that the slave trade has a significant negative impact on fiscal capacity. Instrumental Variable (IV) results confirm Ordinary Least Squares (OLS) findings, and the results remain robust across different measures of fiscal capacity and slave trade. Additionally, we analyze mediating factors using cross-country data and microdata from Nunn-Wantchekon merged with Afrobarometer. Our results suggest that the slave trade’s impact on fiscal capacity operates through weakened public infrastructure and human capital investments. Microdata evidence highlights that while citizens’ perceptions of corruption matter, external factors play a larger role in shaping fiscal capacity.