This presentation aims at introducing the Joint Action Theory in Didactics. This approach stems from comparative didactics in that it develops some of the theoretical tools elaborated in French Didactics (didactic contract, milieu, topogenesis/chronogenesis/mesogenesis, etc.). In the first part of our presentation, we focus on the epistemological background of the theory, by delineating the concepts of language games and semiosis process. The second part of our presentation is devoted to the notion of learning game. We try to show how this notion enables us to enhance our epistemological concern by gathering some theoretical tools. Using learning games characterization aims at “looking in the right place” in order to produce accurate descriptions of the making-meaning process in educational settings. We demonstrate the basic use of JAT in two short transcripts that we share with the presentation of Practical Epistemology Analysis. One of the transcripts come from science education at primary school.