The study aimed to detect the level of activation of supervisors for their roles in the development system of school performance from the perspective of supervisors themselves, and from the perspective of school administrators and their assistants, head teachers, and to identify differences for different variables of the study (gender, type of supervision, years of experience, the number of schools that are supervised by educational supervisor, the job, and the type of school). To achieve the objectives of the study reviewed the literature related to the subject of the study used the descriptive method, and two questionnaires, one for supervisors educators consisting of (49) sentences, and the other for school principals and their assistants and senior teachers made up of (48) sentences, distributed on five axes (definition of the system and its management, cooperation with the school administration to activate the system, cooperation with the senior teacher in the performance of its functions to activate the system, self-evaluation and professional development for teachers, external evaluation of school performance), and after making sure of the validity and reliability of the tools have been applied to a random sample consisted of (150) supervisor of educational, and (58) school principal, and (58) Assistant Director, and (174) a senior teacher in five provinces and areas of education in the Sultanate of Oman in (Muscat, Al- Batinah South, Dhofar, Al- Dakhaliya, and Al- Sharqiya South), and after the statistical treatment of data using the packet statistical SPSS; The study found the following results: 1. Estimates of the study sample of supervisors and school administrators, teachers and their assistants on the first axes in the level of activation of supervisors for their assigned roles in the development system of school performance, ranging from mid-level and higher. 2. No statistically significant differences in the assessment of members of the study sample of supervisors due to the variable number of schools supervised by the educational supervisor, for the supervisors who oversee the smallest number of schools, ranging from (1-5) schools. While there are no significant differences attributable to the variables of gender, type of supervision, and years of experience. 3. No statistically significant differences in the assessment of members of the study sample of school principals and their assistants, head teachers are due to the variable gender, type of school, while there are no significant differences attributable to the variable function. In the light of the results of the study, researcher found anumber of measures proposed to activate the role of supervisors in the development system of school performance in the Sultanate of Oman.