The study aimed to identify the degree of school principals practice of strategic planning and its relationship to developing performance in schools in the Governorate of Muscat to reveal the correlation between school principals practice of strategic planning in developing performance and to reveal the significance of the differences in the averages of the Muscat Governorate school principals estimates of the degree of strategic planning and performance development. According to the variables of the study of gender, academic qualification and the variable of years of practical experience. So, to achieve the objectives of the study, the researcher used the descriptive approach and a questionnaire consisting of (43) items was prepared, and the study sample reached (146) managers. The statistical analysis was done using arithmetic averages, standard deviations, and coefficients. Correlation, (T) test and analysis of unilateral variance and among the most important findings of the study are: • The degree of approval of the sample members for the practice of school principals in the Muscat Governorate for strategic planning and performance development was very high. • There is a strong positive correlation relationship with statistical significance at the level of statistical significance (α = 0.01) between the averages of the sample members estimates of the degree of school principals practice of strategic planning and the averages of the sample individuals estimates of performance development in the schools of Muscat Governorate. • There are statistically significant differences at the level of significance (α = 0.05) between the averages of the sample individuals 'estimates due to the gender variable in the axis of strategic planning and performance development, and in favor of females. • There are no statistically significant differences at the level of significance (α = 0.05) between the averages of the sample members estimates of the degree of school principals practice of strategic planning and the development of performance in the schools of Muscat Governorate due to the scientific qualification variable, years of practical experience. According to the results of the field study, and access to the theoretical literature the proposed procedures were developed to develop the practice of school principals for strategic planning, and its relationship to developing performance in schools in the Governorate of Muscat