This chapter examines four fundamental questions relating to political participation. First, it considers different modes of political participation such as social movements, interest groups, and political parties. Second, it analyses the determinants of political participation, focusing in particular on the paradox of collective action. Third, it explains political participation at the macro-level in order to identify which contextual conditions are conducive to participation and the role of economic affluence in political participation. Finally, the chapter discusses political participation at the micro-level. It shows that both formal associations and informal social networks, configured around family and friendship ties, supplement individual capacities to engage in political participation or compensate for weak capacities, so as to boost an individual’s probability to become politically active.