Young people today encounter many contemplative practices that help them manage stress, build awareness, and connect with others, such as mindfulness, meditation, and yoga. Yet research has mostly focused on classroom- based mindfulness programs, leaving little understanding of the wider range of practices and how youth feel when engaging in them. This study addresses that gap by developing a measure to capture adolescents’ first-hand experiences of contemplation in ways existing surveys cannot. Focusing on early adolescence (ages 10–14 years), a key developmental stage, the project will co-create and test a youth-centered measure of contemplative experiences. Using surveys, focus groups, and think-aloud interviews, the new scale will be refined and validated through rigorous psychometric analyses. The study will also examine the kinds of contemplative practices adolescents engage in and whether participation in a school-based mindfulness social and emotional learning (SEL) program is related to how youth describe their experiences two years later. Finally, it will investigate how social and emotional well-being predicts adolescents’ contemplative experiences. By creating the first comprehensive measure of adolescents’ contemplative experiences, this project will provide researchers and educators with a critical tool to evaluate programs, inform policy, and support practices that nurture resilience, well-being, and human flourishing.