This article expands the conceptual and empirical understanding of relational responsibility in peacebuilding, by unpicking the often ill-defined notion of responsibility into three discrete and hierarchical categories – attributability, answerability and accountability. Present practices of international responsibility for their executive powers in peacebuilding missions are more affiliated with attributability and answerability than accountability. In order to substantiate and elaborate empirically this differentiated account of responsibility, the article explores the UN and EU responsibility mechanisms in Kosovo, focusing on their institutional design, effectiveness and results, as well as highlighting practical limitations and problems. A more specific conceptualization of these practices, allows a clearer analysis of the aims and limitations of the mechanisms in place.