This paper uses aggregate data from the International Labor Organization and microeconomic data from the European Values Study to quantify gender gaps in entrepreneurship, distinguishing between gender gaps in employership and in self‐employment, and study their main empirical determinants. Our sample consists of 40 European countries and varies broadly in terms of institutional background since it includes several ex‐Communist countries. In the aggregate data we observe a gender gap in employers of 59% and a gender gap in self‐employment of 36%. These gaps have remained roughly constant in the 2000-2017 period, although there are wide differences in both their levels and evolution over time and across countries. Using microeconomic data, we find that the incidence of entrepreneurship, employership, and self‐employment among men is much larger than among women, consistent with the gaps estimated using aggregate data. Our regressions show that these gaps are still sizable even after controlling for a large set of control variables that include marital status, age, education, number of children, wealth, the participation of parents and spouse in entrepreneurship, values toward women, social capital, and prior unemployment. We identify important differences between the determinants of these gaps in ex‐Communist countries and in high‐income ones.