As a strategic sector within the tourism industry, health tourism holds significant potential for economic development, increasing foreign currency earnings, and strengthening a nation's competitive position in international markets. In this context, online marketing plays a pivotal role in the industry's growth by facilitating the showcasing of medical capabilities, enabling access to target markets, and fostering trust among tourists. This study aims to explore and articulate a model for health tourism development, with a specific focus on online marketing. Adopting a qualitative approach, the research is grounded in an interpretive paradigm. Data were collected through in-depth, semi-structured interviews with 20 experts and specialists in the field of health tourism; participants were selected via purposive sampling, continuing until the point of theoretical saturation was reached. The data were analyzed using thematic analysis, following the approach developed by Attride-Stirling. The findings reveal seven core dimensions: economic, social, managerial, technological, and infrastructural factors, as well as influencing and influenced factors. Economic factors encompass medical costs and health tourism insurance; social factors include cultural awareness, communication languages, and the utilization of unique local assets; managerial factors involve administrative stability and strategic planning; technological factors cover technology adoption, social media, and health records; and infrastructural factors comprise medical equipment, promotional activities, and service quality. Furthermore, collaboration, communication, team spirit, and government involvement were identified as influential factors in the development of health tourism, while revenue generation, accessibility, and credibility were identified as factors influenced by this development. Overall, the results indicate that the development of health tourism—with an emphasis on online marketing—requires synergy among economic, social, managerial, technological, and infrastructural capacities. The proposed model can serve as a framework for policymaking, strategic planning, and the enhancement of online marketing performance, ultimately aimed at boosting Iran’s competitiveness in the health tourism market.