This article offers the first empirical and cross‐national analysis of citizens’ views about the democratic importance of the public sphere. We first identify three normative functions that public spheres are expected to perform in representative democracies: they provide voice to alternative perspectives, they empower citizens to criticise political authorities and they disseminate information on matters of public interest. We then argue that citizens develop differentiated views about the importance of these democratic functions, depending on (1) their ability to influence political decisions through public debate, and (2) the extent to which voice, critique and information address democratic problems they particularly care about. Drawing on Wave 6 of the European Social Survey, the statistical analysis indicates that citizens in most European countries consider the public sphere very important for democracy, especially its role as a supplier of reliable information. However, certain groups tend to care more about different aspects of the public sphere. More educated citizens are more likely to assign greater importance to all three functions. Members of cultural and sexual minorities are more likely to emphasise the importance of giving voice to alternative perspectives, while citizens dissatisfied with the government are more likely to prioritise public criticism and access to reliable information. Finally, in countries with more democratic public spheres, differences based on education and minority status are wider, while differences based on government satisfaction disappear. These findings support the claim that citizens care more about the public sphere when they can effectively influence political decision making through public debate or when the public sphere addresses democratic problems that are especially important to them. Moreover, our results indicate that citizens see some of the functions that public spheres perform as core aspects of democracy, comparable in importance to free and fair elections and the rule of law. The article thus advances an empirically grounded defence of the centrality of public debate for democracy.