In this paper I argue that that there is a heterodox social surplus approach that has its own account of output-employment and prices, and its own value theory which draws upon various heterodox traditions. Starting with the Sraffian technical definition of the social surplus and then working with a Sraffa-Leontief input-output framework, the particular distinguishing feature of the heterodox approach is the role of agency in determining prices, the social surplus, and total social product and employment. Thus, in the first two sections, the heterodox model of the economy is delineated with respect to the social surplus and social provisioning, followed in the third and fourth sections with the development of a pricing model and a output-employment model and their structural-theoretical properties delineated. In the fifth section the results of the previous four sections are brought together to develop a model of the economy as a whole. The paper concludes with the delineation of the heterodox theory of value.