This study focused on the effectiveness of school heads on appraisal of teachers’ performance in public secondary schools in Kwimba District. The study involved 243 respondents namely 228 teachers whose number was obtained through simple random sampling, 14 heads of schools and 1 District Education Officer for who were selected using purposive sampling. The study used Questionnaires and Interview to collect data. Whereby, both qualitative and quantitative approaches were used to analyze them. The specific objectives were to assess the importance of teachers’ performance appraisal, to assess the effectiveness of school heads on appraisal of teachers’ performance and to identify challenges which face the school heads on appraisal of teachers’ performance. The study found that, appraising teachers’ performance is important for improving the current performance, increasing motivation and accountability, discussing problems and identifying solutions, improving teaching and learning processes and encouraging professional learning and growth. Also, the study found that the heads of school appraise their teachers’ performance, although they are faced with various challenges. These include low level of knowledge, lack of skills, conflicts with the subordinates, absence of tools and lack of commitment. The researcher concluded that, teachers know the roles of the performance appraisal and they are ready to be appraised by their superiors, the heads of schools know their responsibilities which they are supposed to perform, upgrading is not given priority by most of the school heads and the heads of schools use bad leadership styles. Finally, the researcher recommended that, the government must ensure the provision of training for heads of school, OPRAS forms and education for teachers. And the appointment of school heads must base on knowledge, ability and competence.