This research aims to contribute to the enrichment of the scientific study of collective action in contemporary societies. The research sought to examine the relevance and impact of social inequalities on collective action in the European context. The thesis starts with a theoretical discussion around the concepts of social classes, collective actors and collective action, and then presents a structural and cultural analysis of collective action, using contemporary and central tools from the sociology of social classes. At the structural level, we analyze the consequences of inequality (based on class, economic capital, gender, knowledge, labor and politics). At the cultural level, we analyze the impact of egalitarian values, social representations about the state and ideological positions on collective action. In terms of methodology, results were obtained from the "European Social Survey" (2008 and 2006), through a transnational and comparative analysis. The potentialities offered by the combined use of extensive European surveys with national indicators allowed us to extend the problematic of social classes methodologically, analytically and theoretically. The main research findings reveal that collective action in Europe varies according to social class, social inequality and also according to the dynamics of the knowledge society, values, political culture and labor market in different European countries.