Crime and fear have given rise to numerous reactions in the way the built environment takes form. This includes fortification on many scales, from burglar bars on windows and walls around properties to barricades around entire neighbourhoods. This chapter explores the causes and consequences of urban fortification in South Africa. It also considers the implications of crime and urban fortification for socio-spatial order and integration. Some of these consequences contribute to social and economic exclusion, which may reduce opportunities to address poverty and hardship. This chapter makes use of the Drivers-Pressures-State-Impact-Responses (DPSIR) model to illustrate how urban fortification influences the socio-spatial landscape in South African cities. The model shows the need to consider urban security and fortification and their relationship to urban sustainability from a systemic viewpoint, i.e. as an integrated subsystem which is part of a larger system – the city. Finally, the chapter explores possible scenarios in which fortified spaces are an integral part of future urban environments.