Job burnout among dual-job teachers is a phenomenon that, due to psychological pressures, professional conflicts, and structural limitations, leads to a decline in teaching quality and the deterioration of their mental health. Burnout not only harms teachers' physical and mental health but also affects the quality of education. Teachers who experience burnout may struggle to meet students' needs effectively and may even lose their motivation for teaching.This study was conducted to examine the underlying factors contributing to job burnout in dual-job teachers. The research method was qualitative and based on a phenomenological approach. Twelve dual-career teachers with at least a bachelor's degree, working in Kashan schools and with less than ten years of teaching experience, were purposefully selected. Data were collected through semi-structured interviews and analyzed using content analysis. First, the interviews were analyzed by reading them several times and examining the differences and similarities from different angles. Then, considering these differences and similarities, the specified codes were merged and subcategories were determined. In the next step, by re-examining the differences and similarities of the subcategories, separate categories were obtained. The results indicated that job burnout among dual-job teachers can be categorized into nine main themes: professional inefficiency, existential and motivational crises, personal and family conflicts, challenges in balancing two jobs, lack of support and justice, financial problems, job dissatisfaction, mental and psychological issues, and physical exhaustion.The findings indicate that the double pressure of working two jobs simultaneously reduces teachers' motivation and productivity and negatively affects their mental health. To prevent this, it is essential that educational policymakers and schools improve the working conditions of dual-career teachers and provide them with the necessary support. Therefore, the results of this study emphasize the need to identify and investigate the underlying factors of burnout in order to prevent burnout in dual-career teachers.