Is there a gender gap in Latin American attitudes toward women politicians? While scholars of Latin America have examined the role of institutions and quotas in women's electoral success, less attention has been paid to voters' attitudes about women leaders. In this paper, we report on two survey experiments and an observational study in Brazil looking at the effect of candidate gender on vote choice. We asked subjects to chose a candidate from a hypothetical ballot while randomly varying candidates' gender. We find a strong and consistent 5–7 percentage point pro-female bias. Our experiments illustrate a novel approach to testing candidate choice models.