This chapter outlines and discusses different approaches to social ontology and locates Heidegger within a range of contemporary debates. I first discuss various accounts of the scope and method of social ontology by suggesting that social ontology has a restricted scope if it takes the social world to be a distinct domain among others and that, in contrast, has an unrestricted scope if it takes sociality to be an irreducible dimension of what there is. Discussing his general conception of fundamental ontology as well as the development of his early work, I then show that Heidegger’s social ontology is non-reductive and has an unrestricted scope. I then qualify this claim by arguing that Heidegger’s social ontological method can rightly be called transcendental in the sense that he argues that the irreducible social dimension of what there is depends not on empirical social formations but on transcendental relations to others.