Post-conflict cities represent a laboratory in which to explore the substate orientation of security. Based on an analysis of developments in Baghdad, Basra and Falluja since 2003, this article argues not only that security is inherently selective, but also that the exclusionary actions of local or sectarian groups are more influential than those of statebased agents or projects based on security for the individual. The notion of security can accommodate multiple interpretations, but in practice a dominant discourse controls its meaning, and negotiation soon develops into patterns of domination and exclusion. This typically leads to a ‘ghettoization’ of security, whereby specific groups are secure only in specific areas. Security thus reflects the sum of myriad local arrangements. The key issue, therefore, is not whether there can be security for all, but the nature of the concessions made by substate and state-based types of security, and the contrast between them and models based on security for the individual.