Educational theorizing makes use of various tools and perspectives to understand how differentiation processes in education have emerged as responses to socio-historical developments. Drawing on a systematic literature review, this article finds that educational research has framed these responses in five different ways: as structural-functional response; communicative response; cultural-historical response; hegemonic response; and as a response to capability development. Scrutinizing these scholarly understandings of differentiation from a meta-theoretical perspective, the article investigates, firstly, the kinds of knowledge generated within each approach; secondly, how researchers and researched subjects--differentiating agents and differentiated patients--are positioned relative to one another; and thirdly, how these approaches contribute to thinking about inclusion and exclusion in education. Drawing on insights from the author's fieldwork in multi-ethnic Southwest China, each of these five theoretical conceptualizations are interrogated with respect to their potential to accommodate conceptions of individual or collective agency.