Background: The first purpose of the study was to evaluate the validity and reliability of the Automatic Self-Talk Questionnaire for Sports (ASTQS) in the Turkish language and the secondary purpose was to examine the relationship between the quality of the coach-athlete relationship and athletes' self-talk. Methods: 477 athletes (females = 252, males = 225) completed the Turkish versions of the Coach-Athlete Relationship Questionnaire (CART-Q) and the ASTQS. Results: ASTQS showed good psychometric properties in the Turkish language. Findings on the construct validity of the scale were consistent with the original scale's 8-factor structure. The Cronbach's alpha coefficients ranged from 0.65 to 0.91. Furthermore, path analysis results showed that closeness had a direct effect on disengagement, psych-up, and anxiety control. The commitment had a direct effect on somatic fatigue, and complementarity had a direct effect on worry, confidence, and instruction. Conclusions: Finally, the results from the present study indicated that the Automatic Self-Talk Questionnaire provided a reliable and valid measure for Turkish athletes. The results revealed the importance of the coach-athlete relationship in sport and its' role in shaping athletes' self-talk.