Several factors influence adolescents' life satisfaction. At school, peer relatedness and school supportiveness, as well as individual self-perceptions such as academic self-efficacy, promote life satisfaction. Yet school is a context within which risks such as victimization can occur. The aim of this study was to test a model of relations of school factors predicting life satisfaction. We tested the mediator effects of victimization and academic self-efficacy between school supportiveness and peer belonging and life satisfaction. Participants were 2200 6th and 7th grades children attending middle school in Southern Switzerland. Data have been collected with the Middle Years Development Instrument questionnaire. Results showed that the sense of peer belonging and a supportive school environment have a positive effect on children academic self-efficacy and life satisfaction, and reduce the probability of victimization. Victimization, in turn, negatively affects life satisfaction and academic self-efficacy, while academic self-efficacy has a positive effect on life satisfaction.