Objectives: To understand the mediating effect of social support on the relationship between work stress and wellbeing experienced by school nurses. Methods: School nurses from elementary, junior high, high, and vocational schools in Taiwan were selected using stratified random sampling, to whom questionnaires were given to collect the required data. A descriptive analysis, correlation analysis, and hierarchical regression analysis and various mediation methods were performed to examine the mediating effect of social support on the relationship between work stress and wellbeing. Results: School nurses’ social support exerted a mediating effect on the relationship between work stress and well-being. Therefore, increasing school nurses’ social support can reduce the effect of work stress on their well- being. Conclusions: According to the research results, this study recommended that the school and government authorities should provide administrative and policy support for school nurses, and the peer support from other school nurses can enhance school nurses’ work abilities. Professional school nurse organizations should enhance school nurses’ professionalism and facilitate instrument development, promoting a new horizon for student care.