In taking up current discussions in IR, the article argues that behind the historical constitution of world society there is the still ongoing process of modernization. Based on sociological authors such as Marx, Elias and Weber, the concept supplements the classical dichotomy between tradition and modernity with Habermas’s more recent sociological paradigm of the differentiation between system and lifeworld, thereby focusing on modern state formation and its implications for a political sociology of world society. Against the background of this theoretical framework, the article further addresses three interrelated issue complexes of international politics – the state of the nation-state, global community formation and the transnationalization of law. With this sociologically inspired approach to world society, the article aims at contributing to theoretical and empirical debates in both International Relations and development studies.