This report describes an action research study conducted between 1992 and 1995 with 12 New Zealand primary school principals. Prior to this study, major administrative changes in the education system in New Zealand had been introduced, to give schools more responsibility for their own management in conjunction with elected committees of parents. This research sought a model of professional development which would assist principals to implement new ideas and practices, deal effectively with the current issues and problems in their schools and provide skills, challenges and support. This was a qualitative study in which an action researching community, consisting of the principals and an academic researcher, met regularly using peer partnerships and group meetings to provide observation, reflection and evaluative feedback on leadership practice. The questions that guided the research study were: 1. Do partnerships assist in the professional development of primary school principals? 2. If so, in what ways? This research was designed as a conscious effort to not only develop a theory of professional development for school leaders but in so doing, to provide professional development which would help the school leaders to understand and then change their situation. The underlying theoretical principle of praxis was embedded and interwoven throughout the researcher’s and principals’ actions. The research was practical and based on the needs and concerns of the principals involved. In this way it was both a research and development model. The findings were analysed using grounded theory techniques within a structure of action research. Thus, the processes of action research in this research study became a method for the analysis process as well as for that of data collection. The community of researchers were jointly involved in the analysis of the findings in this research. There were 18 months of data gathering using methods of oral and written reflections, interactive interviewing, observations and examination of records. The 12 primary school principals in this study testified that the partnerships’ programme assisted in their professional development. In the words of one principal: This research has made me focus on my own educational leadership. It has led me through a series of processes which has enabled me to reflect on and analyse my own actions. The research has made me take an in-depth look at my own leadership style and has given me the opportunity to observe others. The ways in which these principals believed they had gained from their involvement in the research fell into four major categories. The Partnerships’ programme assisted critical reflection on practice to occur; it increased professional interactions; it assisted in educational leadership development and finally, it established a structure for the principals to use processes of action research for school development. The vehicles for the principals to achieve praxis were reflection and alternative perspectives. Praxis led to emancipatory actions and feelings of agency. The principals’ partnerships, the involvement of the university researcher and the meetings of the community of action researchers, became integral parts of this process. The thesis that is presented rests on the principals’ perceptions that a model of professional development which involves principals in partnership, with the support and challenge from a university academic, can successfully provide the essential components of professional development programmes in which praxis is the desired outcome. This thesis concludes that the Partnerships’ programme assisted in the professional development of these 12 school leaders. The principals, when working together in each other’s schools, created a mild disruption to everyday practice which led to opportunities for reflection on leadership practices. The university researcher also assisted in this intervention process. The combination of the two was effective to enable critical reflection on practice and subsequent change in practice to occur. On the basis of these findings a grounded theory of professional development is offered and recommendations are made for further research in this area.