The contemporary transformations in western societies produce a question already stated by Durkheim a century ago; that is, what enables members of society to practice social solidarity while becoming increasingly more individualistic? This paper analyzes this issue in view of the political socialization of adolescents and its developmental implications. In line with the Durkheimian tradition in developmental psychology established by Piaget and elaborated by Kohlberg, this study hypothesizes that the development of moral autonomy gives rise to a justice-related sense of responsibility that may foster bonds of solidarity within society. This developmental model was tested against the impact of socialization variables in a sample of East and West German adolescents, aged 15 and 18 (n=348). Analyses of the data show a substantial relationship between the development of moral autonomy and the readiness to take responsibility for others in response to justice concerns. The impact of the development of moral autonomy on the formation of a justice- related sense of responsibility depended only minimally on background indicators of political socialization in adolescence (e.g., East or West German origin, the socioeconomic status of parents). In the context of current social conditions, a developmental approach to political socialization is apparently crucial in explaining the emergence of justice concerns giving rise to solidarity. 4 tables, 1 figure, and 66 references