Can capital constraints explain why there are more male than female entrepreneurs in most societies? We study this issue by exploiting longitudinal data on lottery winners. Comparing between large to small winners, we find that an increase in lottery win in period t-1 significantly increases the likelihood of becoming self-employed in period t. This windfall effect is statistically the same in magnitude for men and women; a one percent increase in exogenous income increases the probability of female selfemployment by 0.6 percentage points, which is approximately 10% of the gender entrepreneurial gap. These results suggest that we can causally reduce the gender entrepreneurial gap by improving women's access to capital that might not be as readily available to the aspiring female entrepreneurs as it is to male entrepreneurs.