This study aims to discover the role of administrative supervisors Developing Professional Development of School Principals in Basic Education Schools in Al- Dhahira Governorate in the Sultanate of Oman, from the view of those principals of basic education school and also to obtain proposals to improve this role . To achieve the aim of this study, the researcher analysed the literary which are related to the administrative supervision, and professional development of school principals, beside field survey to discover the role practiced by the administrator supervisor in professional development of basic education schools principals in Al-Dhahira governorate. The study contains a list established by the researcher which is component of (64) paragraph distributed in the eight following fields: planning, administrative organizing, guiding, human relations, evaluation, reactive communication administration, professional development, and technical usage,and after extracting the evidence of stability and honestly which is related to these instruments, the study was distributed on sample of(63)basic school principals of males and females in Al-Dhahira governorate in sultanate of Oman, (51) list has been returned, and after tackling the informations statically ,the researcher reached to following results: - Administrators supervisor practice their role in professional development of basic education schools principals in Al-Dhahira governorate in the Sultanate of Oman in an average level. - There are statistic differentials evidence at the level evidence of (α=0.05) between average samples of males and females in the fields of planning, evaluation, professional development and technical usage for females. - There are no statistic differential evidence at the level evidence of (α=0.05) in samples of individual study estimations about the role of professional development for basic education schools principals in Al-Dhahira Governorate due to experience variation in all study stages in the light of field study and literary analysis, the study leaded to many proposals to react the role of Administrators supervisors in professional development for school principals in Sultanate of Oman, and also to propose another studies about administrative supervision.