This chapter deals with the Security Council’s legitimacy deficit. It goes beyond the standard critique of the Council’s composition and lack of representativeness and delves deeper into the legitimacy and effectiveness of the Council’s processes and performance. Questions about its performance legitimacy can arise in two ways: when it acts irresponsibly, and when it fails to act at all. The chapter posits that the main reason the Security Council is facing a legitimacy crisis today is its failure to act in response to many threats to international peace and security. Accordingly, one way of addressing that crisis is by generating a greater sense of responsibility to act. The chapter offers a set of proposals-underpinned by the twin principles of participation and publicity-to improve the quality of the Security Council’s deliberations, including empowering elected members, engaging regional groups, opening informal processes, and magnifying audience effect through greater public scrutiny.