["Journal of Community &Applied Social Psychology, Volume 36, Issue 3, May/June 2026. ", "\nABSTRACT\nSocial participation during adolescence is a fundamental indicator of active citizenship. Prior research has identified sense of community as an important predictor of social participation. However, literature also suggests that prosocial behaviour and other dispositional factors—such as self‐transcendence values and social dominance orientation (SDO)—may serve as antecedents of participation. Two correlational studies investigated the predictive role of self‐transcendence values (Study 1–2), SDO (Study 1) and sense of community (Study 2), and the mediating role of prosocial behaviour (Study 1–2) in adolescents' informal participation, political participation and volunteering. Study 1 (N = 293; Mage = 13.65 years, SD = 1.94; 52.2% F) revealed a full mediation of the relationship between self‐transcendence values and informal participation through prosocial behaviour only among lower secondary students; no significant indirect or direct effects emerged for political participation and volunteering. SDO, which was expected to be a negative predictor of prosocial behaviour and social participation, showed no significant associations. Study 2, conducted with early adolescents (N = 353; Mage = 12.12, SD = 0.91; 50.4% F), replicated the full mediation of prosocial behaviour in the relationship between self‐transcendence values and informal participation and extended the findings by showing that prosocial behaviour also mediated the association between sense of community and informal participation. These findings suggest that prosocial behaviour may link both dispositional and psychosocial factors to early adolescents' informal participation, highlighting potential strategies for educational interventions and youth policies aimed at promoting active citizenship.\n"]