Abstarct: The aim of this study was to examine the effect of captain identity leadership on individual and team effort of athletes with team cohesion as a mediating variable. The present research was descxriptive-correlational in nature and cross-sectional in terms of time. The statistical population consisted of all adolescent basketball plaxyers in Salah al-Din province, of which 210 participants were selected using a convenience sampling method. The research instruments included three standard questionnaires: the captain identity leadership questionnaire by Stevens et al. (2014), the individual and team effort questionnaire, and the team cohesion questionnaire by Carron and Brawley (1985). To assess the face and content validity of the instruments, the opinions of ten experts and professors of sport management were used, and reliability was confirmed using Cronbach's alpha. To test the research hypotheses, variance-baxsed structural equation modeling was employed. Data analysis was performed using SPSS 23 and Smart-PLS 4 software.The results indicated that captain identity leadership and team cohesion had a significant positive effect on both individual and team effort. Furthermore, team cohesion significantly influenced individual and team effort and acted as a mediating variable in the relationship between captain identity leadership and effort. The findings highlight the importance of the captain's role as an identity leader in sports teams. Captain identity leadership can enhance athletes' motivation and collective effort by fostering a sense of belonging and unity among team members. Additionally, team cohesion, as a mediating factor, emphasizes the importance of coordination and collaboration within the team in improving both individual and team performance. These results can serve as a basis for coaches, sports managers, and training planners to design educational programs and develop leadership in team sports.