We document that women are less represented on corporate boards in Finance and more traditional STEM industry sectors. Even after controlling for differences in firm and country characteristics, average diversity in these sectors is 24% lower than the mean. Our findings suggest that well-documented gender differences in STEM university enrolments and occupations have long-term consequences for female business leadership. The leadership gap in Finance and STEM may be difficult to eliminate using blanket boardroom diversity policies. Diversity policies are also likely to have a different impact on firms in these sectors than in non-STEM sectors.