["Applied Psychology: Health and Well-Being, Volume 18, Issue 4, August 2026. ", "\nAbstract\nIn recent years, stress mindset—how individuals perceive and respond to stress—has drawn increasing attention from researchers. Studies have begun to explore its mechanisms of influence on students' mental health and academic achievement. A randomized controlled trial was conducted in a middle school in China. Two classes were randomly assigned to the intervention group and received a specially designed “Stress Mindset” course based on the B.E.S.T. principle, whereas the remaining two classes served as the control group. A total of 155 students participated, including 78 in the intervention group. The average age of participants was 12.25 years, with 49.70% females. Bayesian Causal Forest (BCF) analysis showed that, compared to the control group, the intervention group exhibited a 0.46 standard deviation increase in stress‐is‐enhancing mindset (95% confidence interval [CI] = [.18, .71]). No significant improvements were observed for other variables. A mediation model supported the intervention mechanism: Group assignment (independent variable) predicted changes in academic motivation through the change in stress‐is‐enhancing mindset (B = .12, SE = .05, and 95% CI [.03, .25]). Process evaluation and qualitative feedback from researchers indicated high satisfaction and acceptability of the intervention. The stress mindset intervention effectively promoted a shift in students' perception of stress as enhancing, offering a novel paradigm for future intervention research. The findings offer a novel paradigm for future intervention research.\n"]