Dissertation (MA Education)The purpose of the study was to examine roles of heads of public secondary schools in teachers‟ professional development (TPD) at workplace in Tanzania, focusing on Kilombero district. The study had two research objectives; exploration/ examination of heads of secondary schools‟ roles; for TPD at workplace and ways of professional development of secondary school teachers at their workplace. The challenges faced by teachers and secondary school leaders due to professional development of secondary education teachers also presented. The study was guided by Stufflebeam‟s (1971) model of contexts, inputs, process and product (CIPP) towards realizing conceptual framework that was in line with study objectives and literature reviewed. The study employed a cross-sectional design. A total of 10 participants were involved in the study, among them, two were heads of secondary schools, four were science and arts heads of departments and four were science and arts subject teachers who were selected purposively. Data were collected through semi structured interview and documentary review and were subjected to qualitative analysis. The findings from the study depicted that, school leadership contributed to TPD through; establishing a culture of collaboration within departments, insisting on teachers‟ supervision, facilitating teachers‟ attendance to workshops and seminars, ensuring that teachers learn from available resources. However, the study depicted a number of challenges facing the secondary school leaders and teachers due to the TPD at the workplace that include shortage of teaching and learning resources, shortage of teachers, poor leadership, lack of fund and poor infrastructure, these, in one way or another restrain eagerness of teachers toward TPD.