Recent research has established the importance of children and adolescents developing a growth mindset for future success and motivation. This research tests believes about fairness, adult trust, and school climate that are theoretically foundational for establishing a cognitive connection between effort and outcome. Regressions and MANOVAS were conducted to understand the direct and indirect relationships between perceptions of justice, adult trust, school climate and growth mindsets.The first study included 363 children from Brazilian public schools and the findings supported our hypothesis that adult trust partially mediates the relationship between justice perceptions and growth mindset. The second study included an adolescent sample (n = 497) from more diverse backgrounds and included a measure of institutional mindset. In this study, school fairness and solidarity mediated the relationship between perceptions of justice on institutional growth mindset. This research can help inform educators and researchers of other constructs necessary to foster a growth mindset.