Background <p>Health risk behaviors pose serious threats to adolescents’ physical and psychological well-being as well as their long-term development. Previous studies suggest that a growth mindset can serve as a positive cognitive resource that may be associated with such behaviors, but the underlying mechanisms remain underexplored. Guided by the Transactional Model of Stress and Coping, this study examined a longitudinal model in which a growth mindset is associated with later health risk behaviors via core self-evaluation and coping style.</p> Methods <p>A three-wave longitudinal study with three-month intervals was conducted using cluster sampling among middle school students in eastern China. Growth mindset, core self-evaluation, coping style, and health risk behaviors were measured by self-report questionnaires. The final sample comprised 534 students (<i>M</i>_age = 12.40, 50.2% male).</p> Results <p>A growth mindset at T1 was associated with fewer health risk behaviors at T3. The total association was primarily indirect: when core self-evaluation and coping style at T2 were included in the model, the direct association between having a growth mindset and health risk behaviors was nonsignificant, whereas indirect effects via core self-evaluation and positive coping were statistically significant, both as separate indirect effects and as a serial indirect effect.</p> Conclusion <p>The findings provide longitudinal evidence consistent with an indirect pathway linking a growth mindset to lower health risk behaviors through more positive core self-evaluation and adaptive coping, thus highlighting these psychological resources as potential targets for health risk behavior prevention efforts.</p>