Purpose: The present study aimed to investigate the effect of a reflective self-talk intervention on athletes’ endurance motor performance, with an emphasis on the moderating role of need for cognition.

Methods: This study employed a quasi-experimental pretest–posttest design with a control group and a 2×2 factorial arrangement (intervention × need for cognition). The statistical population consisted of male athletes aged 18–25 years who were actively engaged in sports clubs and teams in Tehran. A total of 60 participants were purposively selected based on their level of need for cognition (high vs. low) and were randomly assigned within each level to either the reflective self-talk intervention group or the control group (15 participants in each subgroup). Research instruments included the Need for Cognition Questionnaire and an endurance performance test consisting of cycling to exhaustion.

Results: The findings revealed a significant main effect of the reflective self-talk intervention on endurance performance (p < .001, η² = .39), such that participants in the intervention group demonstrated greater improvement in time to exhaustion compared with the control group. Additionally, the main effect of need for cognition (p < .001, η² = .24) and the interaction effect between reflective self-talk and need for cognition (p < .001, η² = .23) were significant.

Conclusion: Overall, the findings suggest that reflective self-talk can serve as an effective strategy for enhancing athletes’ endurance performance and that consideration of cognitive individual differences, particularly need for cognition, is essential in designing sport psychology interventions.