The growth of social inequality in recent decades has a strong urban dimension. In fact, cities are places where such inequalities grow quickly, and have a strong influence on the living conditions and perspectives of different social groups. In this sense, urban segregation becomes an important warning in assessing the existence of disparities that affect the most disadvantaged social groups. Therefore, the aim of this research was to outline the evidence of the phenomenon of residential segregation and housing insecurity on a European scale, and to analyze the case study of Naples, Italy, evaluating the presence of the phenomena of urban segregation and housing insecurity within through the creation of a synthetic index: the “Index of housing deprivation in the neighborhoods of the city of Naples”. After analyzing the extent of the phenomena, we took a step further, seeking to understand whether there have been responses from civil society through protest movements. Indeed, another objective of this paper was to understand why, in the city of Naples, there is no strong social response. In order to give an explanation, we will carry out a comparison with the action of the social movements of Barcelona.