On the issue of abortion, Ireland and Poland have been among the most conservative countries in Europe. Their legal and cultural approaches to this issue have been deeply influenced by the institution of the Catholic Church and its purported role as a defender of an authentic national identity. However, their political climates for abortion reform are increasingly divergent: Ireland has liberalised its abortion law substantially since 2018, while Poland is moving towards further criminalisation with the repeated introduction of restrictive laws (...) in parliament. Both have seen active pro-choice movements who mobilise for reform and widespread non-compliance with their restrictive abortion laws, but the policy impact of these trends varies significantly. What accounts for this difference? This article draws on comparative analysis of Ireland and Poland to assess their divergent trajectories on abortion reform, arguing that the most significant driver of change between the two is the disparity in influence of the Catholic Church on politics and policymaking. (shrink)