The study aimed to identify the performance level of the technical members supervising school performance development system' as perceived by principals, deputy principals and senior teachers in the schools applying the system, and the impact of variables of gender, educational qualification, current career and work experience on the sample responses about the following questions: 1. What is the performance level of the technical members supervising school performance development system as perceived by principals, deputy principals and senior teachers in the schools applying the system in terms of possessing the skills of the effective supervisor? 2. Are there any significant statistical differences at (a s 0.05) in the the performance level of the technical members supervising school performance development system as perceived by principals, deputy principals and senior teachers in the schools applying the system in the Ministry of Education, attributed to gender, educational qualification, current post and experience in the current post? For the purpose of data collection, a questionnaire consisting of (45) items distributed on five themes was administrated among a sample of (1000) principals, deputy principals and Senior teachers. The main results were as follow: 1. The respondents perceived that the level of the technical members performance with a total mean of 3.55 out of 5. 2. The theme of "achievement of the objectives of the system" was ranked first in terms of the performance of technical members with a total mean of (3.61), followed by the theme of " evaluation", the theme of "the professional growth for teachers and school administrators", the theme of " follow-up planning of the management of the school and the senior teachers", and finally the theme of " human relations" 3. There were significant differences at the level of significance (a s 0,05) among the sample responses attributed to the variable of the current post in the themes of human relations and professional growth of teachers and school administrators, differences came in favor of the senior teacher and deputy principals. 4. There were significant differences at the level of significance (a s 0,05) between the perceptions of members of the study sample to the level of technical members performance due to the variable region and the differences were in favor of Al Buraimi and the Al Batinah North. 5. There were significant differences at the level of significance (a s 0,05) among the sample responses attributed to the variable of educational qualifications and the differences were in favor of qualified higher diploma and upper. 6. There were significant differences at the level of significance (a < 0,05) among the sample responses attributed to the variable of experience. The differences were in favor of the experienced (11 years and over). 7. There were significant differences at the level of significance (a s 0,05) among the sample responses attributed to the variable of gender in all themes and in favor of females.