Summary: The project will develop and validate measures on adolescents’ and emerging adults’ social, cultural and political identity, their sense of belongingness in different groups, their participation in physical and online communities, their interest in democratic participation and their trust in democratic institutions. The measures will be used to explore and understand 13- and 15-year olds’ political and community engagement in almost all countries in Europe through the survey “Health Behaviour in School-aged Children. A WHO-Collaborative Study” as well as emerging adults turned 18 years of age. Further, qualitative information on adolescents’ and emerging adults’ perspectives of what is political and community engagement to them and how to they act on or communicate their perspectives on key societal issues will be collected and analyzed. The project will also identify formal and informal structures for youth democratic participation in a selected number of countries. A key focus here will be to explore adolescents’ and young adults’ participation in communities on social media platforms to learn where and how they communicate their political and community engagement. Finally, the project will develop policy initiatives with adolescents and emerging adults and policymakers using the Co-Create Dialogue Forum tool, including piloting of strategies in Living Labs. Marginalized groups will be given particular emphasis in the analyses to identify need for specific focus in policy development strategies.