This study aimed to compare the effectiveness of positive psychology intervention and process–outcome mental simulation training on academic well-being, achievement emotions, and academic self-efficacy among procrastinating students. A randomized controlled trial with three groups was conducted: a positive psychology intervention group, a process–outcome mental simulation group, and a control group. Participants included 45 procrastinating male high-school students from Zahedan (2024–2025), randomly assigned to three groups of 15. Interventions were delivered in structured group sessions, and data were collected across pre-test, post-test, and five-month follow-up using standardized instruments. Data analysis employed repeated-measures ANOVA and Bonferroni post-hoc tests using SPSS 27. There were significant main effects of time, group, and time×group interaction for all variables (p<.001). Bonferroni comparisons showed both interventions significantly outperformed the control group in improving academic well-being, achievement emotions, and self-efficacy (p<.001). The positive psychology intervention showed the strongest effects on academic well-being and self-efficacy, while process-based simulation produced the largest improvements in achievement emotions. Differences between post-test and follow-up were nonsignificant, indicating stable intervention effects. Both positive psychology and mental simulation interventions are effective in enhancing academic and emotional outcomes among procrastinating adolescents and can be implemented as efficient school-based programs to reduce procrastination and promote academic functioning.