The electoral system is an important factor influencing female representation in Parliament. There is a consensus that a proportional representation (PR) system is more beneficial for women than a majoritarian system. Since there is a lot of variety in PR systems and since recent literature suggests that how actors cope with institutional provisions should be looked at more closely, we have investigated why women receive fewer votes in an open-list PR system. More in particular, it was our aim to find out whether women receive fewer votes because of voter bias or systemic bias. We have analyzed three variables influenced by systemic actors (parties, society and media) that have a substantial effect on the number of votes: media attention, campaign expenditures and list position. Our analysis of the 2003 federal Belgian elections shows that women are disadvantaged on these three variables and that as a consequence they obtain fewer votes. There is no voter bias, but a systemic bias. These disadvantages can be due either to individual characteristics influenced by education and society (less ambition, less convinced of capabilities, and so on) or, more importantly, to party-or media-related factors (a.o. list composition, designation of campaign budgets and spokespersons). Acta Politica (2010) 45, 468-490. doi:10.1057/ap.2010.6