Smart social tourism, as an emerging approach combining smart technologies with social participation, has opened up new capacities for sustainable development in local communities. Amid rapid technological advancements and increasing social complexities, effective policymaking in this field is an undeniable necessity for countries like Iran, which possesses rich cultural, historical, and geographical diversity. This study aims to design a policymaking model for the development of smart social tourism in Iran. It is a fundamental research based on a fieldwork approach. The participants consisted of two expert groups: Academic scholars in tourism policymaking (theoretical experts) and active managers in the tourism industry (practical experts). Qualitative data were collected through semi-structured interviews comprising six main questions and the flexibility to ask follow-up questions. Data analysis was conducted using the grounded theory method. Findings revealed that causal conditions—including social capital of host communities, economic motivations, institutional capacity in tourism planning and policymaking, and digital transformation of tourism—affect the core phenomenon of smart social tourism. The core phenomenon, in turn, is shaped by contextual conditions (such as the tourism institutional system and smart infrastructure) and intervening conditions (such as inefficiencies in spatial distribution). These influence the strategies and actions adopted, which include drafting a national development plan for social tourism, spatially just planning, smart innovations to ensure fairness in tourism experiences, strengthening policymaking institutions and governance structures, empowering human resources, and institutionalizing the discourse of responsibility and justice in public tourism culture. Ultimately, these strategies lead to key outcomes, including a balanced distribution of tourism opportunities, enhanced social dynamism in destinations, improved national tourism positioning, and comprehensive, inclusive, and sustainable development of social tourism.