Urban protest is often carried out by citizens’ committees: that is, political groups that mobilize on issues affecting a small territorial area, use various forms of protest, and are organized in very loosely structured forms. Based on interviews with members of citizens’ committees in Florence, this article discusses their identities, strategies and organizational models, as well as their interaction with local authorities. Active mainly in issues of pollution and security, the Florentine committees frame their demands in terms of defending or improving quality of life in a defined territory. Mobilizing citizens who have often had previous experience in voluntary and/or political associations, citizens’ committees evidence a strongly participatory organizational model, with, however, notably discontinuous levels of activity. Whilst privileging moderate forms of protest, citizens’ committees also seem to have more and more channels of access to the institutions of local government, which sometimes perceive them as a source of information and aggregate consensus. The quality of the interactions between citizens’ committees and the public administration plays an important role in determining the extent to which this type of urban protest produces social capital.