The goal of this study is to examine to what extent gender quotas have contributedto recent increases in women’s representation in parliaments. The results show thatthe effect of quotas on women’s representation in parliaments increased over timeduring the first decade of the twenty-first century, and that in the mid and late partsof the decade quotas are an important determinant of women’s representation in parliaments.However, the results from this study demonstrate that several countries thatuse gender quotas still have low levels of female representation in parliaments, whichindicates that the designs of the quotas are important.