Objective: This study examined the direct and indirect associations between physical education teachers’ professional ethics and students’ social skills, considering the mediating role of teacher–student relationships.

Method: This applied, cross-sectional correlational study was conducted among 629 physical education teachers in Chaharmahal and Bakhtiari Province during the 2024–2025 academic year. Five counties were randomly selected as clusters, followed by proportional allocation and simple random sampling within the selected clusters. A total of 119 teachers completed standardized questionnaires assessing professional ethics, teacher–student relationships, and teacher-rated student social skills. Data were analyzed using SPSS and partial least squares structural equation modeling (PLS-SEM) in SmartPLS.

Findings: Professional ethics was positively associated with teacher–student relationships (β = .487, p < .001) and students’ social skills (β = .481, p < .001). Teacher–student relationships were also positively associated with social skills (β = .285, p < .001). The indirect association of professional ethics with social skills through teacher–student relationships was significant (β = .139, p = .002, 95% CI [.063, .236]).

Conclusion: The findings indicated that part of the association between physical education teachers’ professional ethics and students’ social skills was explained through the quality of teacher–student relationships. Accordingly, teachers’ fairness, respect, responsibility, and empathy are more likely to be associated with students’ social development when they are reflected in daily interactions and supportive relationships.