Head teachers of primary schools have to deal with a lot of shifting managerial environments, which sometimes makes them ineffective in their expanding responsibilities. Therefore, providing targeted in-service training has never been essential. Head teachers in Kenya's Marakwet West Sub County were asked to participate in the KEMI Diploma in Educational Management Course as part of this study. The research design was a descriptive survey. The sample consisted of 38 head teachers chosen through stratified random sampling from 57 schools whose heads had completed the KEMI Diploma in Education Management, 42 teachers chosen at random, and 13 chairpersons of the Board of Management chosen intentionally from the same schools. Data was gathered through the use of questionnaires. The information was summed up and introduced utilizing recurrence tables, charts and rates. The study found that head teachers were motivated by the need to improve their skills, a raise in pay, and a higher job grade. In order to encourage teachers to participate in useful professional development programs, the study suggested that head teachers' job evaluations include an audit of skill requirements, continuous short-term refresher courses in areas that were studied, decentralization of training, and recognition of head teachers' academic achievement through promotion and salary increments. The study found that there were gaps between the course content and the actual management skills that school managers need, such as ICT skills and financial management bookkeeping. The TSC's selection, promotion, and deployment of head teachers of primary schools should also be reviewed, according to the study.