The modern school is a multi-layered and complex institution. For inclusive values and practices to embed in educational systems the nature of school culture and the change process must be considered. Qualitative data was gathered during a year-long ethnographic study of inclusive change in a co-educational high school. This paper applies a model of culture to demonstrate that the development of inclusion within a whole school culture is a process of continued personal and collective reflection, re-negotiation, and experience carried out over a sustained period of time. In order to foster the sustained development of inclusive cultures in schools it is vital to understand the nature of change within school culture, and to provide the time to reflect on deeply held beliefs.