This chapter examines the philosophical grounds for linking responsibility with capacities to reason and to judge in the light of moral considerations. It discusses five different accounts that connect responsibility and rationality, the work of: Susan Wolf, R Jay Wallace, the jointly authored work of John Martin Fischer and Mark Ravizza, Angela M Smith, and Pamela Hieronymi. Through these authors’ contributions, the chapter argues that the notion of rational ability is central to understanding and justifying practices of responsibility. Although there has been clear progress in debates about this connection, however, understanding the notion of rational or moral ability still poses profound challenges. One reason for this is suggested: such abilities may have constitutive connections with practices of holding responsible and of taking responsibility – connections that have yet to be fully explored in the literature.