["Journal of Community &Applied Social Psychology, Volume 36, Issue 3, May/June 2026. ", "\nABSTRACT\nStudies investigating the role of social cohesion in schools and neighbourhoods on adolescents' well‐being remain limited. This study aimed to develop a more nuanced understanding of adolescents' well‐being using a person‐centred approach, and to examine how social environments within school and neighbourhood settings are associated with well‐being profiles. Latent class analysis was employed to identify distinct well‐being profiles among adolescents studying in Helsinki (N = 10,681). Multilevel multinomial logistic regression analyses were conducted to examine the associations between school and neighbourhood settings and well‐being profiles. Among the adolescents, 49% exhibited excellent, 20% mixed, 14% moderate and 18% poor well‐being. According to the final model tested, adolescents attending schools characterised by low social cohesion were more likely to experience poor well‐being compared to those within more cohesive schools. Notably, if all adolescents had attended schools with good social cohesion, the probability of exhibiting excellent well‐being would have increased, while the probability of poor well‐being would have decreased. In intervention development, priority should be given to enhancing social cohesion, with particular focus on adolescents belonging to a high‐risk group with poor well‐being.\n"]