A fundamental challenge plagues the global peacebuilding community: how can technocratic approaches further longer-term outcomes like altering young people’s attitudes and beliefs about peace and violence? In response to this global challenge, Peacebuilding Legacy analyses the long-term effects of peacebuilding programmes involving children and young people. It unpacks the concept of peacebuilding legacy through the lens of time, transformation, and intergenerational peace, and develops unique qualitative cues for measuring legacy. If models resonate strongly with the local context, they are likely to be adopted over time. Successful institutionalisation of project models through handing them over to national organisations or government departments holds the key to stronger local ownership. Organisational learning and reflection can support this process through a more strategic approach to programming and post-exit studies. Regarding attitude change, the book finds that the media and peace education projects that targeted individuals’ ingrained beliefs and values but overlooked the role of group social norms had only limited effects. To shift the values, practices, norms, and beliefs of the younger generation, the mindset of the older generation must also be targeted. Changes in the legal, political, economic, and other social institutions are critical for long-term and meaningful transformation. This requires adopting an ecological model of peace.