This article used theory, historical records, and empirical research to make a case that inclusive education, in which students experience significant proportions of their day in the age-appropriate contexts and curriculum of general education, is a research-based practice with students who have extensive support needs. We begin by noting that there are regressive trends occurring in educational placements in our country and that these are causing alarm. Next, we establish guidelines for defining a useful, research-based practice. These guidelines include considering what education should be achieving for all students as a standard and using a view of scientific causality that acknowledges complexity. We then show how constructs from ecological theory and group processes theory, which provide accounts for human growth and learning, relate to location of educational services (i.e., context) and curriculum (i.e., content) decisions. Throughout this discussion, we show educating students using an inclusive education approach is supported by these constructs, whereas other widely used special education are not. We then review both historical and empirical data from institutions and schools and show that these data provide empirical support for the primary theoretical position of this article--that context, together with curriculum content, matter crucially when educating students with extensive support needs. We concluded that there is theoretical and empirical support for using general education contexts and curriculum content and for not using other contexts and curriculum content both in educating students with extensive support needs and in conducting related research.