Abstract The present study aimed to investigate the role of visionary leadership of school principals on the professional development of teachers through the mediation of psychological empowerment. A descriptive correlational research design was applied by using the structural equation method. The statistical population of included all the primary school teachers of Saqez city, which were announced as 901 individuals, among whom 260 teachers were selected as a research sample by simple random sampling method and according to Krejcie and Morgan table. visionary leadership, psychological empowerment and professional development questionnaires were used to collect data. The validity of questionnaires was confirmed confirmatory factor analysis, and the reliability of questionnaires was confirmed with Cronbach alpha method (above 0.7). Data analysis was conducted by structural equation modeling, using Lisrel software. Research results indicated that the visionary leadership style of school principals and the psychological empowerment of teachers have a positive impact upon the professional development of teachers at the level of 0.01. The visionary leadership of school principals has a positive indirect effect on teachers’ professional development at the level of 0.05 due to the psychological empowerment of teachers. According to the obtained fit indexes, it can be argued that the model of the relationship between visionary leadership of principals and the professional development of teachers has a good fit due to the mediating role of empowerment.