This interdisciplinary book explores how the policy goal of gender equality operates in arguably the most masculinist area of politics: peace and security. Gender equality was set on the international peace and security agenda with the adoption of UN Security Council Resolution 1325 in 2000 and the inception of the Women, Peace, and Security (WPS) agenda. Celebrated internationally as an outcome of feminist advocacy efforts, the WPS agenda has over time become a site of contestation. Security institutions have questioned the placement of the gender equality objective within the peace and security sector, whereas feminist advocates have expressed their concerns about the capacity of security institutions to support gender equality in meaningful ways. Drawing on insights of nearly seventy UN, government, international and local civil society experts, the book offers a systematic take on key gender equality debates within the WPS agenda in the case studies of UN Security Council, ASEAN and Pacific Islands Forum, and Governments of the Philippines and Australia. By looking back at the dilemmas of gender equality policymaking and their paradoxical effects in conflict and post-conflict situations, the book also looks forward to the third decade of the WPS agenda and the long-term impact of the agenda on the political struggle for gender equality in peace and security.