Abstarct: The present study aims to investigate the impact of environmental policies of sports clubs on fans' sustainable purchasing behavior, considering the mediating role of green brand image. This research is applied in terms of objective and descxriptive-survey in terms of nature. Data were collected using standard questionnaires, and data analysis was performed through Structural Equation Modeling (SEM) using statistical software (such as Smart-PLS). The path analysis results indicated that the environmental policies of sports clubs have a significant positive impact on green brand image and fans' sustainable purchasing behavior. Furthermore, the positive influence of green brand image on sustainable purchasing behavior was confirmed. T-statistics for all hypotheses were greater than 1.96, and P-values were less than 0.05. The research findings confirm that green brand image acts as a crucial mediator, strengthening the relationship between the club's environmental actions and consumer behavior. By adopting green policies, sports clubs can enhance fans' perceptions and encourage sustainable purchasing behavior while fulfilling their social responsibilities.