Archaic state formation simultaneously involved political integration and socioeconomic differentiation, which many archaeologists consider mutually reinforcing processes. Differentiation is considered to have consisted primarily of status and specialization, forms of heterogeneity that ultimately supported state integration. This paper addresses the role of differentiation in the Andean polity of Tiwanaku (A. D. 500–1150). Specifically, it evaluates expressions of social identity in relation to differences in status and specialized production in the urban settlements of Tiwanaku and Lukurmata. Patterns of ceramic style are compared with other types of material culture and residential activities. Multiple lines of evidence suggest that, in the context of a potent and ubiquitous state culture, significant social boundaries persisted at multiple social scales, ranging from urban corporate groups to more encompassing regional affiliations. At larger scales identity potentially involved some degree of political autonomy, as it did in later sociopolitical organizations in the south-central Andes. For several hundred years, Tiwanaku rulers, facing profound social diversity and enduring local identities, emphasized incorporative strategies of integration, leaving a great deal of productive management and sociopolitical organization in the hands of local groups. Social boundaries played critical roles in state formation and centralization, and ultimately may have precipitated its disintegration.