The importance of improving schools to transform the delivery of education so that every student has the opportunity to reach her or his true potential is incontestable. School level professional development of teachers is one route towards school improvement. The purpose of this study was to explore school level professional development practices of three primary schools in Ethiopia. Qualitative case study was the basis of the study. Data from the participants (teachers and education officials) were obtained through in-depth and 'elite' interviews. Policy and school documents were also analysed. Field notes about the school environment and events were used to triangulate the data. The study showed the prevalence of tensions between in-service development through cluster resource centres and teachers' feelings of imposed change. It also showed instaff training, mutual classroom observation and experience sharing as forms of professional development in the schools. The study revealed teachers do not undertake action research due to lack of knowledge and skill to do it. In addition, the study found out that school level professional development is constrained due to teachers living distant from the school, teachers' clinging to traditional attitudes, poor management, lack of material support from education authorities and failure of the centre to reconcile central and local conditions. The findings suggest that there is a necessity to empower schools and teachers by developing their capacity in terms of knowledge, skills and material support to enable them decide about their professional development activities. This in turn necessitates collaborative work among education authorities, schools and organizations interested in teacher development, and also a strong partnership between schools and higher education institutions. The thesis is organized in nine chapters. Chapter one deals with educational change in Ethiopia, informed by change theories. Chapter two presents school level professional development ideas and policy formulation in Ethiopia. Teacher development models, approaches and management of school level professional development are discussed in chapter three. Chapter four is about the methodology of the study. Chapters, five, six and seven describe the case schools. Chapter eight provides cross case analysis. The final chapter presents concluding remarks and suggestion.