Advocates have long worked within and outside the United Nations (UN) to institutionalize recognition of youth as positive participants in peace and security. However, despite the disproportionate impact of conflict on youth, attention to constructive role of youth in peacebuilding has been largely neglected. In 2015, a convergence of efforts and events saw the UN Security Council pass a groundbreaking thematic resolution, Resolution 2250 on Youth, Peace, and Security (SCR2250), which recognizes for the first time youth's positive role in responding to peace and security challenges. This article draws on analysis of civil society and UN documents, and interviews with key members of the coalition of UN and civil society actors who advocated for this resolution. It demonstrates that partnership with youth in the case of Youth, Peace and Security (YPS) advocacy offers an opportunity to extend understandings of agenda setting in new ways. It examines the issue framing as well as the actors, access, and allies that enabled the success of a coalition of diverse actors working toward normative change. Efforts toward SCR2250 were unique because of the key role of youth-led advocacy, making youth themselves central not only as beneficiaries but also as creators of a new principle for the norm of youth participation in peace and security.