This study lends new insights into the hitherto-unexplored relationship between entrepreneurial thinking and the sustainability of small and medium-sized enterprises (SMEs) in Iran, mediated by social media. The goal was to investigate the effect of entrepreneurial thinking, mediated by social media, on the sustainability of SMEs in Iran from January to February 2022. The statistical population comprised 407 SME managers based in the Pardis Technology Park and the Science and Technology Town (Iran). Using Cochran’s formula, a sample of 197 SME managers was selected via the simple random method. The data were collected using a 5-point Likert scale questionnaire with 25 questions, the reliability and validity of which had been examined and confirmed. The data were analyzed in SmartPLS 3. The results revealed that entrepreneurial thinking plays a pivotal role in managerial decisions and is a crucial factor in the sustainability of SMEs in Iran. Managers, as creators and reformers of the internal business environment, can establish and enhance a strong link between business sustainability and employees’ ability to acquire entrepreneurial thinking.