Convention theory is one of the theories in the body of social sciences research on sports. In particular, it developed in reaction to the predominance of sociology stemming from the theory of Pierre Bourdieu and his concepts of “habitus” and “field.” Convention theory makes it possible to consider more of the processes underlying the modes of coordination between different actors. It also connects actors’ actions more closely to the forms of justification they produce. This chapter is structured around five themes that illustrate the use of convention theory in different areas of sociology of sport: the analysis of sports organizations, spaces, and facilities; disciplines and sectors of sport; sports practices and practitioners; and technological and scientific controversies. The chapter demonstrates that sport is well-suited to the application of convention theory, whose contribution lies in the attention given to the arguments and forms of justification underlying the actions and participations of actors. Additionally, the theory is suited to analyzing the development of individuals’ actions, their modes of collective coordination, and their ideas and conceptions.