This research aims to examine the impact of human resource management practices as a mediating variable in the relationship between strategic planning and job performance, from the point of view of employees and administrators in the Education Directorates in the Sultanate of Oman. The research problem centered on the poor performance of some employees due to the huge administrative burdens and the overlapping of tasks and specializations they undertake. Therefore, it is important to study the relationship between the three variables mentioned above. This is to provide the scientific basis for officials in the education directorates in the Sultanate of Oman to take new corrective measures to develop staff performance. The researcher followed a descriptive survey approach and relied on a cross-sectional sample to collect data. The researcher developed a questionnaire consisting of 76 items and distributed the questionnaire to 750 participants in four educational governorates; of which, 340 questionnaires were valid for statistical analysis. The researcher analyzed the data using SPSS and performed the confirmatory factor analysis (CFA) using AMOS to assess the validity and reliability of the questionnaire. The researcher used structural equation modeling (SEM) to study the relationships between research variables. The results revealed a statistically significant impact of strategic planning on human resource management practices and employee performance. The results also showed a statistically significant effect of human resource management practices on employee performance, and a mediating effect of human resource management practices in the relationship between strategic planning and employee performance. Based on the previous results, the researcher presented a set of recommendations, the most important of which are: (i) the need to create work environments capable of contributing to the development of strategic planning, (ii) improving human resource management practices and job performance in educational directorates, and (iii) paying attention to developing staff performance and developing their professional skills.