The present study aimed at revealing the role of the self-assessment teams in supporting the system of developing school performance in post-basic education in Al Batinah North Governorate in Sultanate of Oman. The study followed the descriptive approach. The questionnaire was used in collecting data and information. The study was applied to a sample of 220 male and female teachers. The study found that the role of self-assessment teams in supporting the system of developing school performance in post-basic education in Al Batinah North Governorate in Oman was generally high and was between high and average level for the study areas. The role of the senior teacher (resident supervisor) ranked first with a high level of appreciation. Then the role of male and female teachers came in the second place and at a high level of appreciation. The role of the principal and his/her assistant came in third place with a high level of appreciation as well, while the role of students came in the fourth place with an average level of appreciation. In the fifth and last place the role of parents came with an average level of assessment also. In addition, the results revealed that there were no statistically significant differences at the level of (a < 0.05) in the responses of the study sample of male and female due to the variables of job title and academic qualification. However, the differences were in the sex variable and in favor of females and years of experience in favor of those who have more than 10 years. The study presented number of recommendations, the most important of these are the following: Paying attention to held professional development programs for members of the self-assessment teams of the schools, whether at the level of the Ministry of Education, its educational directorates or schools, and including members of the community in the self-assessment teams of schools. In addition, to increase the number of parents and students in these teams. Moreover, the interest of school administration in providing opportunities for parents and students to participate actively in self-assessment processes and to make their opinions and proposals respected and appreciated.