The purpose of this article is to bridge the gap between critical theory as understood in the Frankfurt school tradition on the one hand, and social ontology understood as a reflection on the ontological presuppositions of social sciences and social theories on the other. What is at stake is the type of social ontology that critical theory needs if it wants to tackle its main social ontological issue: that of social transformation. This paper’s claim is that what is required is neither a substantial social ontology, nor a relational social ontology, but a processual one. The first part of this article elaborates the distinction between substantial, relational and processual social ontologies. The second part analyzes the various ways in which this distinction can be used in social ontological discussions. Finally, the third part focuses on the various possible social ontological approaches to the issue of social transformation.