What is the material context of constitutional order? The purpose of this paper is to offer an answer to that question by sketching a theory of the material constitution. Distinguishing it from related approaches, in particular sociological constitutionalism, Marxist constitutionalism, and political jurisprudence, the paper outlines the basic elements of the material constitution, specifying its four ordering factors. These are political unity, the dominant form of which remains the modern nation-state; a set of institutions, including but not limited to formal governmental branches such as courts, parliaments, executives, administrations; a network of social relations, including class interests and social movements, and a set of fundamental political objectives (or teloi). These factors provide the material substance and internal dynamic of the process of constitutional ordering. They are not external to the constitution but are a feature of juristic knowledge, standing in internal relation and tension with the formal constitution. Because these ordering factors are multiple, and in conflict with one another, there is no single determining factor of constitutional development. Neither is order as such guaranteed. The conflict that characterizes the modern human condition might but need not be internalised by the process of constitutional ordering. The theory of the material constitution offers an account of the basic elements of this process as well as its internal dynamic.