The chapter introduces the concept of affective citizenship as an innovative and promising avenue to explore and revisit the relationship between states and subjects in contemporary societies. In contrast to the bulk of research that has rather neglected the affective and emotional dimensions of citizenship, this concept departs from the rationalist paradigm that undergirds most political concepts. Instead, it centers the analysis of the governance through and of affects and emotions by exploring the policies, discourses, and institutional practices of states, as well as acts of affective citizenship such as resistance or compliance by citizens and non-citizens alike. Building on earlier feminist, queer, and postcolonial critiques of citizenship, emerging literature on affective citizenship deciphers how mechanisms of exclusion and inclusion proceed through the affective registers of citizenship. Given the ongoing problematization of migration, belonging, and identity in contemporary societies, shifting attention to the affective dimensions of political boundary making is critical for a comprehensive understanding of affective societies.