The March issue of International Affairs, guest-edited by Paul Kirby and Laura J. Shepherd, analyses the UN’s Women, Peace and Security (WPS) agenda 15 years on from the adoption of the first WPS resolution by the UN Security Council. In achieving its aim to maintain international peace and security, the Security Council and has recognized the centrality of gender issues through the adoption of eight, inter-related resolutions on women, peace and security. On the back of these, governments were encouraged to produce National Action Plans detailing how they would advance gender equality at home and abroad and organizations such as the EU and NATO have incorporated elements of the WPS agenda into their defence and security policies. But has the agenda lived up to its ambitions in its first 15 years? The articles in the special issue extend and enrich debates about WPS in innovative ways, reaching beyond implementation. Roberta Guerrina and Katharine Wright come closest to the question of implementation, but in the context of investigating the extent to which the EU’s engagement with WPS discourse is evidence of, or a contributory factor in, the construction of the EU as a leader in promoting ‘gender norms’. All but one of the other contributors focus on the gaps and silences in WPS discourse and practice: Fionnuala Ní Aoláin explores the applicability of WPS principles in an era of ‘new wars’ in which much security strategy is focused on counterterrorism; Jamie J. Hagen interrogates the WPS agenda from a queer theory perspective, to explore the heteronormative logics that tend to structure both discourse and practice; and Marjaana Jauhola focuses explicitly on the marginalized subjects of women, peace and security, exploring the ways in which WPS discourse is predicated upon a construct of the ‘good woman’. By contrast, Soumita Basu analyses the performative dimension of WPS in her exploration of state practice at the UN in relation to WPS. Cutting into this issue in a different manner, Sam Cook offers a compelling account of the ways in which WPS is performed by civil society actors at the UN, arguing that by examining this performance we can gain a profound understanding of the dynamics of power, legitimacy and authority that render WPS discourse intelligible, and mobilize support for the agenda into the future. Finally, Kirby and Shepherd provide an assessment of the past 15 years of WPS, an analysis of its tensions in the present, and a sketch of its possible near futures. The issue also includes the revised text of the 2015 Martin Wight Lecture, given by Christopher Hill, and a comprehensive literature review of the Responsibility to Protect by Ramesh Thakur.