This article compares the contemporary Czech and Polish women's movements and demonstrates that there are significant differences in their strategies. While the Polish women's movement is more active in mobilizing the population and uses both transactional and participatory strategies in order to achieve its goals, the Czech women's movement focuses more on transactional activities, such as lobbying, setting up cooperation with national and international organizations, and negotiating with the authorities, as well as on educational activities. The article explains why these differences occur and why during the last decade the Polish women's movement has attempted at mobilizing the population successfully, while the Czech women's movement has not tried to organize any mass mobilizations. Based on interviews with women's organizations in Poland and the Czech Republic, we argue that institutional factors can explain these differences. This includes such factors as the role of the reformed, postcommunist women's organization in each country and the political opportunity structures. The most important political opportunity structures include a law in Poland that force the parliament to debate a law proposal if civil society organizations can get 100,000 signatures, as well as the facility for residents to allocate 1% of their income taxes to a registered civil society organization of their choosing. Another important difference in the political opportunity structures has been the types of institutional arrangements made to accommodate European Union's demands for gender mainstreaming.