How growth mindset shapes math achievement: The moderating role of classroom practices and the mediating role of engagement across adolescence.

Although the positive role of a growth mindset in adolescent math learning is widely recognized, little is known about the moderating role of classroom practices, the mediating role of engagement, or developmental patterns in these relations. One thousand three hundred thirty adolescents in Grades 8, 10, and 12 attending 14 U.S. urban public schools (M_age = 15.50, SD_age = 1.56; 54% female; 69% White, 26% Black; 49% low-income) participated in a longitudinal study conducted over one academic year. Students completed measures of motivation and reported on the classroom practices of their math teachers. Math course grades were obtained from school records. Results show that the overall effect of a growth mindset on math achievement was positive, and growth-oriented classroom practices positively moderated this effect. However, both the overall mindset effect and the moderation effect declined in upper grades. The mediating role of engagement in the association between a growth mindset and math achievement was positive but modest on average. Importantly, this mediation effect was stronger in the presence of growth-oriented classroom practices, particularly in Grade 10. These findings highlight the importance of supportive classroom practices and developmental stages in enhancing the motivational and academic benefits of a growth mindset. (PsycInfo Database Record (c) 2026 APA, all rights reserved).