School engagement is crucial for adolescents' academic performance. This study identifies that perceptions of barriers despite schooling significantly influence such engagement. When students in a class share these perceptions, a unique classroom climate emerges, impacting overall school engagement. Specifically, this study explores how adolescents' perceptions of barriers despite schooling affect school engagement, highlighting the mediating role of social mobility beliefs and the moderating influence of life history strategies. Analyzing a sample of 1,025 Chinese adolescents, multilevel linear modeling reveals that class-level perceptions of barriers despite schooling negatively affect individual school engagement, with social mobility beliefs acting as a vital mediator. When students perceive high barriers, their belief in educational success diminishes, leading to decreased motivation and engagement. Additionally, individual differences in life history strategies shape this relationship; slower strategists demonstrate high engagement only when social mobility beliefs are strong, while faster strategists maintain low engagement regardless of belief levels. These findings underscore the need for educators and policymakers to address perceived barriers and tailor interventions to enhance students' social mobility beliefs, fostering a more equitable educational environment that supports all learners.