Collaboration is an increasingly popular topic in mathematics education due to its potential to foster students' learning. The purpose of this article is to draw attention to the semantic philosophical theory of inferentialism and its value for investigating students' collaboration. We suggest that Brandom's inferentialism can serve as a valuable theoretical resource to overcome certain issues of existing theoretical viewpoints on student collaboration. In particular, we argue that inferentialism may help to understand the individual and social nature of collaboration as intertwined. We illustrate our inferentialist approach using data from two scenes taken from video-recorded group work sessions from a fifth and seventh grade primary school class in Sweden. The topic in both classes was data generation in statistics.