study aimed to identify the degree to which school administration supervisors practice their job roles and its relationship to the level of leadership skills among school principals and their assistants in the Sultanate of Oman. To achieve the objectives of the study, the descriptive approach was used. A questionnaire consisting of (48) items was used to collect data from a sample of (317) male and female principals, and their assistants, in government schools from the Governorates of Al Dakhiliyah, Muscat, North Al Batinah, and South Al Sharqiyah in the Sultanate of Oman. One of the most important results reached by the study is that the degree of school administration supervisors’ practice of their functional roles in the Sultanate of Oman from the point of view of school principals and their assistants was generally average. The results also showed that there were statistically significant differences at the significance level (α ≤ 0.05) between the averages of the study sample’s estimates of the degree of school administration supervisors’ practice of their functional roles attributed to the gender variable (male, female) in the planning dimension in favor of Females. The results of the study also showed that the level of leadership skills among school principals and their assistants, from their point of view, was generally high. The results also showed that there were no statistically significant differences at the significance level (α ≤ 0.05) between the averages of the study sample’s estimates of the level of leadership skills among school principals and their assistants, attributable to the variables of gender, job title, and educational governorate in all dimensions. The results of the study showed that there was no statistically significant correlation at the significance level (α ≤ 0.01) between the degree to which school administration supervisors practice their job roles and the level of leadership skills among school principals and their assistants in the Sultanate of Oman in all dimensions. Based on the results of the study, a number of recommendations were suggested, including holding workshops and specialized training courses for school administration supervisors to increase their efficiency in how to prepare, evaluate and implement school plans, and for the school administration department in educational directorates to organize the exchange of visits between school administration supervisors with other governorates and with friendly countries.