Purpose: The school principals’ competence plays an important role in improving the education system. As a result, this study aimed to investigate and present the competency model of high school principals. Methodology: The current research was applied in terms of purpose and mixed (qualitative and quantitative) in terms of implementation. In the qualitative part, the research population was the educational management experts of Guilan province in the academic year of 2021-22, and according to the principle of theoretical saturation, 15 of them were selected as a sample using targeted and snowball sampling methods. In the quantitative part, the research population was the principals of the second year high school in Guilan province in the academic year 2021-22, and according to the table of Krejcie and Morgan, 127 of them were selected as a sample by stratified random sampling method. The research instrument was a semi-structured interview in the qualitative part and a researcher-made questionnaire in the quantitative part, whose psychometric indicators were checked and confirmed. The data of the qualitative part were analyzed by open, axial and selective coding method in Maxqda software, and the data of the quantitative part were analyzed by exploratory factor analysis method in Amos software. Findings: The results of the qualitative section showed that 137 indicators, 17 components and 5 dimensions were identified for the competence of high school principals; so as to include the dimensions of belief (with the components of cognition, belief, value and behavior), rational (with the components of discretion power, future studies and effective decision-making), personal (with the components of creating a positive environment, needs assessment, mental health and the flourishing of talents), managerial (with the components of human/general skills, perceptual/maturity skills and specialized/leadership skills) and educational (with the components of teaching and learning process, educational supervision and guidance, and educational evaluation). Also, the results of the quantitative section showed that the factor load and the average variance extracted of the dimensions and components were higher than 0.50 and their content validity and reliability ratio with Cronbach’s alpha method was higher than 0.80. In addition, the Competency model of high school principals had a good fit and each of the dimensions had a significant effect on the corresponding components and each of the components had a significant effect on the corresponding indicators (P<0.05). Conclusion: According to the competency model of high school principals, planning to improve and promote the competence of school principals through the identified dimensions, components and indicators seems necessary.
