The purpose of this research was to develop a structural model for predicting subjective well-being based on educational, social, emotional, physical, and security climate of schools through mediation of emotion regulation among junior high school female students. This research had an applied, correlational design. The statistical population of the study comprised all junior high school female students in public schools in Tehran in Districts 2, 7, 11 and 18. The drawn sample (N= 630) was selected using multi-stage cluster sampling method. The instruments included the 2015 National School Climate Survey, Subjective Well-Being Scale (SWS) (Keyes & Magyar-Moe, 2003), and Affective Style Questionnaire (ASQ; Hofmann & Kashdan, 2010). Structural equation modeling was performed to analyze the data. The results showed that there was a positive direct relationship between school climate and self-regulation (p<0.01, β=0.297). In addition, a direct positive correlation was observed between school climate and subjective well-being (p<0.01, β=0.862). The results demonstrated that emotion regulation played a mediating indirect role in the link between school climate and subjective well-being. Finally, it was found that the direct path coefficient between self-regulation and subjective well-being was positive and significant (p<0.01, β=0.098). Hence, it can be concluded that schools are the most important place for boosting mental health in adolescents and a rich and positive school climate can pave the way for promoting resilience in students and regulating their emotions.