This study investigates the relationships among peers' perceived support, life satisfaction, and student engagement in academic activities. Three hundred and fifteen Iranian students (172 boys and 143 girls) who were studying in one suburb of Tehran participated in this study. All participants were asked to complete Peers' Perceived Support scale (PPSS), Student Engagement in Academic Activities scale (SEAAS), and Brief Multi-dimensional Students Life Satisfaction Scale (BMSLSS). Structural equation modeling was used to analyse the data. According to the results, there are significant positive correlations between components of peers' perceived support, student engagement in academic activities, and life satisfaction in pairs. In two examined models, the direct and indirect effects of peers' perceived support on student engagement in academic activities and life satisfaction were significantly positive. In addition, life satisfaction and student engagement in academic activities had a mediating role and bi-directional effect in the surveyed models. In sum, the results of this research endorse not only the importance of peers' perceived support in enhancing student engagement in academic activities and life satisfaction but also the cross-effect of student engagement in academic activities and life satisfaction variables on each other.