This paper offers an analytical framework in order to capture the various channels for the involvement of citizens in democratic systems. It introduces the notion of 'opportunity structures for citizens' participation' (OSCPs) and analyses seven dimensions of OSCPs. This analytical framework is then applied to the political system of the EU. The paper argues that a closer look at the EC institutions' work during the few years since the adoption of the Maastricht Treaty reveals an increased focus on citizens' involvement. However, as will be shown here, only indirect and non-binding, largely informal OSCPs have been implemented so far. With a view to the current Intergovernmental Conference (IGC) and democratic reforms even afterwards, the article concludes with some proposals for innovative OSCPs at the Euro-level.