This paper is focused on the theoretical background of the comparatist approach in didactics (Mercier, Schubauer-Leoni & Sensevy, 2002).In the first part of this presentation, we show how the comparatist approach can be viewed against the background of two necessities. First, avoiding the main limitations of specific didactics by documenting the actual practices of teaching and learning. Second, understanding how the subject matter shapes teachers’ and students’ action. In the second part of this paper, we consider some theoretical roots of the comparatist approach. This approach has been developed by attempting to bridge the gap between some educational research, and social science research, cognitive sciences, and philosophy. We first particularly focus on the question of structure and agency, as it has been worked in comparative didactics. We then elaborate on the questions of transmission of culture and cultural change, from a didactical viewpoint, as it has been built in the comparative approach. The last part of the paper aims to present a recent development of comparative didactics, the joint action theory in didactics (JATD). The JATD is designed to amplify the “actional turn” and the “anthropological tension” of comparative didactics.