Most research on women’s political representation has focused on structures, comparing levels of representation in cross-national studies. Based on theories about ‘formative moments’, this Paper will discuss which factors have contributed to historical changes in women’s parliamentary representation, with focus on the role of actors, including political parties, voters and women’s movement campaigns. Based on a data set of nominations and electoral results in all Danish elections since women’s suffrage (1918-2015), this project will be able to analyze the dynamics between party placement of the candidates and voters preferential voting. Denmark is one of the few countries in the world, where the political parties themselves can choose between open, semi-open and closed electoral lists - from election to election, even with local variations. This makes Denmark a unique case for studying the effect of open versus close lists for changes in women’s representation. In the public discourse women were long blamed for their low representation, and voters have been seen as the central factor behind the increase in the number of women elected. However, we need to scrutinize the role of the parties as gatekeepers to elected positions, and the dynamics between women’s NGOs, voters and party nominations from one election to the next.