Women are still underrepresented in positions of power and have limited access to the most prestigious policy areas. As a consequence, women do not have the same opportunities as men to influence policy-making. We have theoretical reasons to believe that the politics of committee assignments give room for female discrimination. We assess differences in committee membership using unique fine-grained data on members of German state parliaments from 1948 to 2016 and provide several measures of committee importance. With decomposition methods we test whether observable qualifications and experience, electoral incentives and structural aspects help explain gendered committee assignments. If anything, we find that female marginalisation becomes more pronounced as more women enter state parliaments. Observable characteristics and structural aspects explain these patterns only partially. We conclude that women remain systematically disadvantaged in the most relevant policy domains.