The aim of this study is to identify the sources of job stress facing secondary school's principals in the Sultanate of Oman and whether there are significant statistical difference between means of job stress sources according to sex, age, and administrative experience. To achieve the objective of the study, the researcher analyzed the relevant literature review and developed a 90-item questionnaire, classified according to the following dimensions: job nature, work relationship, principal's role, principal's personal aspects, professional development and job satisfaction, work climate, administrative constraints and the school system. The validity and reliability of instrument used were ensured. The sample of the study consisted of 246 individuals, representing all the principals of secondary school in the sultanate of Oman. To answer the questions of the study, the researcher used means, SD's, Rank, T-test, one-way ANOVA and scheffe's test. The main findings of the field study were as follows: In the Sultanate of Oman, the most common sources of job stress experienced by principals of secondary school during their professional life, were, in descending order: sources related to job nature, administrative constrains, and lastly, professional development and job satisfaction. In all indicated dimensions, sources of job stress were highly rated among the secondary school principals in the Sultanate of Oman. 3. There were no significant difference at a = 0.05 between the means of job stress dimensions for secondary school principals in the Sultanate of Oman due to their sex.. There were however, significant difference at a= 0.05 between means of job stress dimensions for secondary school principals in the Sultanate of Oman due to their age and job experience. In the light of literature review and the findings of the field study, several recommendations are being suggested such as, initiation of various training courses and workshops for principals working at secondary school level, to develop, for instance, their anti-stress skills, time management and others. Further study should be conducted in order to investigate other sources of job stress at other levels of the educational system in the Sultanate of Oman, using other variables.