Slovenia introduced electoral gender quotas in 2004 first for the elections to the European Parliament. This successful amendment of the electoral law was preceded by several unsuccessful attempts in the 1990s, when proposals to introduce quotas either into the electoral law or into party laws failed one after another in parliament. Slovenia now has electoral gender quotas for elections at all three levels (local, national, European), but with different outcomes for women’s presence in politics. The paper explores the reasons for these differences and identifies barriers to more effective implementation of gender quotas in politics in Slovenia . The analysis focuses on the effects of the electoral system and the specific features of the various quota regulations (size, implementation, placement mandate and sanctions), the importance of political body, etc. and tries to identify the relative weight of these elements.