Social segregation is associated with social fragmentation and exclusion, often considered as social pathologies that require a remedy. Public spaces are envisaged as accessible spaces of co-presence, sociability, interaction and exchange, which could link the fragments together and generate counterweights to centrifugal and fragmentary social forces. This chapter examines whether and how far the public space can be a response to social segregation, fragmentation and exclusion. It analyses the social and economic processes that lead to social segregation as well as the spatial and political theories and practices that are developed in response. The chapter is organized in six sections. After the introduction, the second section outlines the social dimensions of segregation: the ways in which the power imbalances inherent in social differentiation and stratification are reproduced and represented in spatial segregation. The third section discusses the economic dimensions of segregation and the various roles of the public space in relation to the market: as a place, an asset, an instrument, or a distraction. The fourth section analyses the historical trajectory of social reformists and revolutionaries who have developed spatial theories in urban planning and design, partly revolving around the integrative power of the public space. The fifth section engages with political theories, particularly about the role of the public space in relation to combating segregation by the state, civil society and community. The sixth section provides a brief conclusion. The chapter argues that accessible spaces that would offer the possibility of non-commodified social encounters, inclusive expressive presence and active participation can play a noticeable role in democratic social development, not as determinants of social behaviour, nor for the creation of an imagined homogeneous totality, but for helping the different parts of society being in continuous interaction with each other.