Do parties respond to inequality? Despite the growing relevance of this topic due to rising economic disparities, our understanding of party competition over redistribution remains limited. Previous research argues that rising inequality determines public appetite for redistributive policies as well as parties’ supply thereof. Yet, existing research has used broad salience scores of various social-economic policies from party manifestos rather than parties’ distinct stances on economic inequality. Moreover, the role equality structures play in party competition over inequality has remained both undertheorized and understudied. This paper proposes remedies for both issues. We introduce a novel dataset on party stances on economic inequality, equal chances, and equal rights for twelve OECD countries over five decades (1970-2020). These data enable direct tests of the theoretical mechanisms of party responsiveness to different patterns of inequality. In substantive terms, we dismiss a general and uniform pattern of party responsiveness across countries. Instead, we argue that party competition over redistribution depends on both the predominant conception of equality and a welfare state’s capacity to absorb rising levels of inequality. Thereby, our findings contribute to growing debates over the capacity – and willingness – of parties to engage with rising economic inequality.