Georg Simmel is one of sociology’s most influential early figures, although arguably his work has been under-utilized in many scholarly fields, including sport studies. Some of Simmel’s most important theoretical and substantive arguments are deployed to develop a sociological analysis of a specific sports subculture: the ‘Tartan Army’ of supporters that travels to Scotland football matches. Of particular interest are Simmel’s formal sociological standpoint, differentiation of social and cultural forms, development of dualistic thinking, analyses of human sociability, writings on ‘the stranger’ and ‘the adventure’, and his concern with individuality in modern metropolitan culture. In applying Simmel’s insights, I explore the formal emergence and organic development of the Tartan Army as a distinctive supporter culture. The Tartan Army, like many sports crowds, affords an outstanding study in Simmelian sociability, while providing adventure and a possible escape from our overwhelming modern culture. The article concludes by considering Simmel’s wider utility within the sociology of sport.