The aim of the present study was to identify the factors influencing the sustainable development of sports tourism in Iran. This research is applied in nature and employs a qualitative methodology using thematic analysis. The statistical population included university professors and experts in sports management, tourism, and urban planning; managers of tourism agencies; and Ph.D. researchers in sports management and tourism. The research sample was selected from this population using purposive and snowball sampling methods. The data collection tool was semi-structured interviews conducted with 15 experts, continuing until theoretical saturation was reached. The validity of the study was confirmed by relevant experts, and the reliability was obtained using the intra-coder agreement method, reaching 84%. The findings revealed 67 key points, 14 concepts, and 6 main categories. These main themes included: individual characteristics of sports tourists, enhancement of tourism infrastructure and services, economic dynamism of sports tourism, management of sports tourism destinations, tourism brand management, and sustainable tourism development. Accordingly, the sustainable development of sports tourism requires coordinated interaction among human, infrastructural, managerial, and environmental factors. It is recommended that policymakers, sports managers, and tourism stakeholders adopt an integrated approach and engage in long-term planning aligned with local capacities to pave the way for the flourishing of sustainable sports tourism in Iran.