This thesis explored the introduction of a new physics curriculum in New Zealand secondary schools. It was part of a nationwide overhaul of the whole school curriculum from primary to secondary schools, initiated in the early 1990s. The study of curriculum change is inextricably woven with teacher change, as the teacher is seen as central to any real change in curricula in the classroom. Some theories of teacher change are reviewed here and synthesised into a list of criteria relevant to bringing about effective change in teachers and their practices. A sociocultural perspective emerged as being a useful theoretical approach in analysing and explaining these processes of curriculum change and teacher change because it takes a holistic approach that deals with 'people, places and things' and the discourses involved therein. In particular, Wenger's sociocultural theory was used to study the introduction of a new senior physics curriculum. His terms 'reification' and 'participation' were seen to apply to this research: the curriculum document was taken to be a reified communication artifact, and 'participation' is involved in every stage of its development and implementation. In the context of this theorising, data was procured from in-depth interviews with the three curriculum writers and ten physics teachers in and around a provincial city in New Zealand. The teachers were interviewed three times over a period of three years: before, during and after the first year of implementation; namely 1996 to 1998. The interviews showed that most of these ten physics teachers did not undergo any significant change in their teaching because of the introduction of 'Physics in the New Zealand Curriculum'. The reasons or barriers identified, such as lack of guidelines and clarity, and contentment with their own existing practice, were aligned with factors that have been identified by other researchers as important influences on teachers undergoing change, such as clarity of change and need for change. Three key elements were identified from these issues emerging from the data as necessary conditions or resources for teacher change: knowledge, support and time. In the present study, there was very limited knowledge held by the teachers about 'what', 'how' and 'why' changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had little time to focus on and reflect on the change. A model of curriculum change, incorporating Wenger's notions of 'reification' and 'participation', but extended to include 'dereification' emerged from the data. 'Dereification' highlighted an important stage whereby the curriculum document as an artifact, needed to be incorporated into the plane of lived experiences of teachers. The introduction of the term 'dereification' supported the development of this model of curriculum change incorporating teacher change whereby the model outlined processes of reification and dereification involved in a mandated curriculum change. The model of curriculum change developed here also contained a screen that symbolises the lack of intersubjective linkage between teachers and the designers of the new curriculum. There was no follow-up teachers' guide, not enough explanation of the curriculum document, no direct communication between the writers and the teachers, and insufficient professional development for the teachers using it. The research findings led to three propositions: the curriculum document as a key artifact was not sufficient to effect a curriculum change; the lack of transparency of the curriculum document development was a constraint on teachers' commitment to the curriculum change; and the lack of support for teachers in their dereification of the curriculum document impacted negatively on curriculum change. The key elements of knowledge, support and time identified as crucial for teachers to effect any real change in their practice are critical at different points in the model of curriculum change. It is suggested that using such an interplay between the factors underlying teacher change and the sociocultural analysis of curriculum change, might enable more pro-active intervention at the various stages of the process of a curriculum change to effect a real change.