Gratitude, as a core construct in positive psychology, has gained increasing attention in sport psychology research. Despite the cultural and ethical significance of this concept in Iran, no valid instrument has been available to assess gratitude specifically in Iranian athletic populations. The present study aimed to evaluate the psychometric properties of the Persian version of the Sport Gratitude Questionnaire (GQ-S) among Iranian athletes. After conducting a back-translation procedure and confirming content validity by a panel of experts, a sample of 339 Iranian athletes (193 males) completed the GQ-S. Subsequently, the factor structure, convergent validity, discriminant validity, and reliability of the questionnaire were examined. Confirmatory factor analysis (CFA) supported the satisfactory fit of the six-item, single factor structure (CFI = 0.993, RMSEA = 0.044). Convergent validity was supported, as the average variance extracted (AVE = 0.504) and composite reliability (CR = 0.86) met the recommended thresholds. Discriminant validity was also established, as the square root of the AVE for each construct was greater than its correlations with other constructs. The internal consistency of the GQ-S was high (Cronbach's α = 0.84, McDonald's ω = 0.86).The Persian version of the GQ-S has acceptable psychometric properties.