Public education stakeholders are becoming aware of the new and challenging problems encountered by principals and other school administrators. Despite a growing awareness of the importance and challenges of school principals, there is limited research on the in-service training needs of school principals in developing countries. Specifically, there is a void in the literature as it pertains to in-service training needs of principals in a small developing country such as Jamaica. Principals are the ones who create a vision of leadership and learning, develop a positive school climate, manage the organization, and interact with the external school environment. However, keeping administrative and instructional leadership skills up to date is an ever-present concern for any school system. Therefore, it is imperative to examine the perceptions of Jamaican principals on the competencies needed for principalship outside of the job descriptions of principals stipulated by the Ministry of Education, Youth, and Culture. This study examined the differences in perceptions among principals regarding the needed competencies as identified by research on effective school studies, and it provides additional opportunities to move toward consensus for the position of principal in Jamaica. The research identified differences in perceptions related to competencies and in-service training among current school principals with regard to selected demographic characteristics (age, gender, experience, qualification, specialization, school size, and geographical region) and ascertained the preferred modes of in-service training for principals in each of the selected principal competency areas. (Contains 1 figure and 2 tables.)