Abstract Financial development shapes export sector performance because exporters need external finance and face credit constraints. Previous empirical research has relied largely on single-country studies. The Exporter Dynamics Database (EDD), which features firm-level exports from over 60 countries, reveals differences in the microstructure of the export sector across countries. In this paper, we first provide new evidence that these differences are related to cross-country variation in financial development and structure. Second, we combine the EDD and multidimensional data on financial development with a global database on export diversification. This study is the first to examine how macrolevel export diversification is determined by the microcharacteristics of the export sector. This approach is novel in the empirical literature on export diversification. According to our cross-country analysis, access to domestic financial services positively contributes to export diversification by increasing the number of small exporters, as financial services ease the credit constraints these exporters face.