Purpose: In-service training programmes in educational planning and administration are indispensable for enhancing teachers’ performance. In Uganda, the schools’ administrators and educational policy makers consider investing in in-service training of teachers. The study was purposed to develop workable recommendations, to address the continued poor performance of students in private secondary schools in Kyenjojo District in Western Uganda. The study was guided by four research objective; to find out the types of in-service training programmes provided at St. Joseph’s Hill Secondary School in Kyenjojo district; to determine the contributions of in-service training programmes to teachers’ performance at St. Joseph’s Hill Secondary School in Kyenjojo District; to gauge on how effective the in-service training programmes are promoting effective supervision of students by teachers at St. Joseph’s Hill Secondary School in Kyenjojo District and to find out how teachers’ service delivery affect students’ performance at St. Joseph’s Hill Secondary school in Kyenjojo District. Expectancy theory guided the study.Methodology: The study employed qualitative research method and it was guided by a case study design. The study employed a non-probability sampling procedure. A total of 8 administrators, 26 teachers, 30 students, 1 District Education Officer and 1 District Inspector of Schools were selected. In data collection, the study used Interview guide and Focused Group Discussions for the selected sample. Face to face Interviews were conducted. The data collected was analyzed qualitatively.Results: The findings revealed that in-service training programmes for teachers exist though not consistent but once or twice in a year. The in-service training programmes have contributed to the improvement of teachers’ welfare in regards to acquisition of skills that helped the teachers in teaching. There are different types of in-service programmes offered to teachers. These programmes have contributed to teachers’ performance in the areas of providing exposure to teachers, lesson planning, handling learners, building relations with learners, marking and setting of exams, improvement in time and classroom management, plus inspiring learners to achieve their academic potential and many others.Recommendations: Based on the research findings, the researcher recommends that in-service training providers and school administration put extra efforts on teachers’ supervision.