This study aimed to investigate the professional development for secondaryschool principals in the sultanate of Oman in terms of professional developmentstrategies and their effectiveness , perceived needs, and barriers toprofessional development , and whether there were statistically significant differences that could be attribute to the participants' sex, qualification and administrative experience. To achieve the objective of the study, the researcher analyzed the relevant literature and developed a 62-item questionnaire, classified according to the following dimension; the usage of professional development strategies, the effectiveness of the strategies, professional development needs , professional development difficulties. The sample of the study consists of 145 individuals, representing all the secondary school principals 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 Tukey test. • The main findings of the field study were as follows: 1- The most common professional development strategies conducted among . secondary school principals are self development and guided circulars. 2- The most effective professional development strategies that were used for secondary school principals , were self development and guided circulars. 3- There were significant difference at a = 0.05 between the usage of the professional development strategies for secondary school principals and the effectiveness of the professional development strategies , in favor of the effectiveness. 4- All the professional development needs that were included in the questionnaire were accorded higher and moderate assessment..... 5. The professional development for the secondary school principals in The Sultanate of Oman is facing difficulties. 6- There were no significant difference at a = 0.05 between the mean of professional development for secondary school principals In The Sultanate of Oman that could be attributed to sex, or qualification, 7- There were significant difference at a = 0.05 between the mean of professional development for secondary school principals In The Sultanate of " Oman that could be attributed to administration experience. In the light of literature and the findings of the field study, several recommendations have been suggested