Our study deals with sport socialization in terms of citizenship development. It compares two different sport contexts: institutionalized and competitive sport and self-regulated street sports. It aims to articulate, analyze, and discuss the collected data based on two complementary studies, respectively dealing with legal consciousness (Long, Pantaléon, Faccenda, and Bruant, 2009) and responsibility (Long, Pantaléon, and Bruant, 2008). The results stand in contrast to current beliefs about these two kinds of practice. The conceptions of citizenship that adolescents highlight are related to the contextual characteristics of their sport socialization. Whereas institutionalized individuals highlight a vertical and normative citizenship, self-organized sportsmen display a horizontal and interactive citizenship.