Misalignment between students' communal values and those expressed in classrooms is an obstacle to academic engagement, especially in mathematics, and especially for racial ethnic minority and female students. Using 10 schools across the United States, we conducted a longitudinal field study in 8th grade mathematics classes to investigate: (a) how perceptions of communally oriented classrooms influence student outcomes in early adolescence, (b) what psychological processes mediate these relations, and (c) whether the influence of perceived communal practices in classrooms have similar or different effects on students with varying social identities based on race, ethnicity, and gender. Results showed that middle school classes that emphasize communality (both social relevance of math and peer collaboration) significantly predicted stronger math self-concept, more behavioral engagement, and better performance in math. These associations were mediated through three psychological processes-belonging, challenge, and self-efficacy. Among racial ethnic minority adolescents, feelings of belonging and challenge in math class were key psychological processes that enhanced math learning outcomes. These processes were activated when classes connected communal values to math. Finally, communal learning contexts benefited girls and boys equally. In sum, communal values practiced by emphasizing social relevance of academic content and using collaborative learning practices engage all students, especially students of color, at a formative period of academic learning in mathematics. (PsycInfo Database Record (c) 2022 APA, all rights reserved).