The purpose of this paper is to demonstrate the ways in which creating and sustaining authentic inclusion requires significant alterations to more than the programmatic regularities that characterize schools (Sarason, 1996). Data from ethnographic case studies of inclusive schools in the United States, United Kingdom and Portugal are drawn upon to illustrate significant features that characterize these schools. The multiple dimensions of their inclusive cultures include both implicit and explicit assumptions, values and beliefs that are shown to be central to the ways school staff interact with one another and students. Although the analysis presented in this paper illustrates the importance of understanding the multiple dimensions of school cultures for the operation of inclusive schools, it also highlights the limits of a purely cultural analysis. Educators faced with threats to the sustainability of the vision articulated by the Salamanca statement will also need to understand and respond to the broader political contexts operating in the 21st century. (Contains 3 tables.)