<p>This study examines how switching to a mixed electoral system affects the level of women’s representation in national parliaments compared to the original system. Political science theories suggest that the type of electoral system influences the level of female representation in parliaments. Therefore, it is reasonable to expect that changing to a mixed system will bring changes. We combine two levels of analysis. First, we closely examine six countries that have shifted from majoritarian or proportional systems to mixed systems to assess the impact on women’s representation in parliaments. To ensure that changes in women’s representation are not merely a result of global trends, we compare each country’s share of women in parliament with a country of similar culture and the same initial electoral system, but where the electoral system has not changed. Second, we conduct a large global crossnational comparison using multivariate regressions to examine the broader effects of adopting mixed systems. As expected, our findings show that moving from a majoritarian electoral system to a mixed system increases women’s representation in parliaments. However, unexpectedly the findings show that moving from a proportional system to a mixed system does not decrease women’s representation in parliaments.</p>