This study investigates the relationship between employee wellbeing and wellness tourism sustainability in Sri Lanka, and examines the mediating role of job satisfaction in this relationship. It aims to bridge the gap between theory and practice by exploring the complex dynamics shaping the future of the wellness tourism industry. The study adopts a quantitative research design, using online surveys to collect data from 394 employees working in the Sri Lankan wellness tourism industry using simple random sampling technique. The survey measures employee wellbeing, job satisfaction, and perceptions of wellness tourism sustainability using validated scales. The data is analyzed using partial least squares structural equation modeling (PLS-SEM) and mediation analysis. Furthermore, the results support the hypotheses that employee wellbeing positively affects wellness tourism sustainability, both directly and indirectly through job satisfaction. The findings suggest that job satisfaction partially mediates the relationship between employee wellbeing and wellness tourism sustainability, implying that employee wellbeing not only directly contributes to sustainability but also indirectly enhances it by fostering greater job satisfaction among employees. Moreover, this study provides valuable insights for industry stakeholders, policymakers, and academicians to develop and implement strategies that promote both employee wellbeing and sustainable practices within the Sri Lankan wellness tourism industry. The study also contributes to the growing body of knowledge on employee wellbeing in the tourism sector, particularly within developing countries. By prioritizing employee wellbeing, the industry can improve work-life balance, attract and retain talent, and ultimately deliver authentic and enriching experiences for tourists, contributing to Sri Lanka's economic and social prosperity.