<p>Athletes at all levels experience setbacks to sport performance that hinder goals and impact motivation and wellbeing. In two randomized controlled trials, we tested the viability of athletes to learn from a cognitive-based Setback Solutions Intervention intended to enhance perceived control and behavioural strategy intentions, and lower indecision about setback management. Study 1 focused on testing the intervention feasibility, fidelity, and effectiveness of setback management for 81 postsecondary student-athletes in the USA and Canada (M_age = 22.69). ANCOVAs tested differences between conditions (treatment, control) for Time 2 (post-treatment) setback-related indecision, perceived control, and behavioural strategy intentions, controlling for Time 1 (baseline) levels of each outcome, and setback experience. Athletes in the treatment (vs. control) condition reported lower Time 2 indecision and greater perceived control over setback management. Study 2 tested pre-registered hypotheses for these effects in 201 postsecondary student-athletes from the USA and Canada (M_age = 23.54 years). Study 2 incorporated a six-week follow-up post-intervention (Time 3) and additional psychosocial wellbeing outcomes (e.g., rumination, likelihood to seek social support). The findings were consistent with Study 1 evidencing the effectiveness of the intervention to decrease indecision and increase perceived control over setback management. The implications of these findings are discussed in terms of the development and potential of the intervention for widespread delivery to student-athletes encountering adversity in sport.</p>