With the rapid growth of knowledge and technology, teachers should also keep up by participating in development programs. The conditions governing schools can have a great impact on teachers' interest and motivation to attend professional courses. The current study seeks to study the potential relationships between teachers' individual characteristics and motivation to participate in such courses. Also, the mediating role of working conditions in the school is also investigated. The statistical population included teachers of different levels of schools in Nour. The data were collected using questionnaires of teacher self-efficacy, teacher beliefs about learning, and teachers' perception of working conditions. The data were analyzed through multilevel regression. The findings showed that four school characteristics, including transformational leadership, work pressure, emotional pressure, and support of colleagues, have a decisive and direct impact on teachers' motivation for professional development. At the same time, factors such as performance autonomy and received colleague support also have an indirect and moderating effect on the relationship between teachers' personal characteristics and their motivation for professional development. The results of the study can be useful for school leaders and policy makers in order to adopt strategies to increase teachers’ motivation for professional development.