Transformational leadership is one of the most important factors for the success of organizations and sports teams. Transformational leaders inspire and motivate members by paying attention to their individual needs, which enhances their motivation and performance. On the other hand, team pride can also influence members' loyalty to team activities. The present study aimed to investigate the mediating role of team pride in the relationship between transformational leadership and the loyalty of sports team members. This was a descriptive-correlational study. The study population included all karate athletes in the National Super League in 2023, of which 263 individuals were selected as the sample using non-probability sampling. The measurement tool in this research was a valid questionnaire. The collected data were analyzed in SPSS 26 and Amos 26. The results showed that transformational leadership had a positive effect on loyalty to sports activities and authentic pride, but a negative effect on the hubristic pride of karate athletes. Authentic pride positively influenced loyalty, while hubristic pride was not affected. The mediating effect of authentic pride was confirmed, indicating that transformational leadership through enhancing authentic pride positively affects loyalty to sports activities. The findings suggest that to understand athletes' loyalty, transformational leadership should be displayed in the karate community by respecting athletes' opinions, increasing their autonomy, and improving their authentic pride, which enhances their loyalty to sports activities.