Ethnic identity is a fuzzy concept for several reasons. On the one hand, the very question of what is an ethnic group is not an easy one to answer. On the other hand, once this is established for a specific case, it is yet another task to define who belongs to it, and who does not, and how stable such assignments actually are. This is as true for Central Asia as for any other place in the world, and the fact that, for earlier periods of history, the records—both native ones and others—use a great variety of terms for human populations, does not make it any easier. Thus, it is largely unclear, which of the tribal groups or early statehoods correspond to a contemporary understanding of ethnicity. Anthropological scholarship on Central Asia has, by contrast, stressed the rather vague and floating categories that people in the region used to define themselves and others. According to this view, the creation of ethnic groups was largely a product of more or less artificial engineering during Soviet times. Before, local communities and extended kin groups, regularly reshuffled and redefined in history, were of much greater importance for people’s identification and alliances than language or assumed genetic ties. While there is some truth in that, the picture is more complex. Particularly among the Turkic-speaking groups in the region, a steady process of consolidation set in following the decline of the Mongol Empire, resulting in the emergence of contemporary ethnic groups out of earlier configurations. The underlying concepts of attachment and self-understanding vary, however, and can be distinguished in two different modes, roughly corresponding to the divide between nomadic and sedentary groups. Among the former, the idea of patrilineal descent, or a genealogical model, is at the bottom of internal divisions as well as external demarcation; in the oases, the prime criteria are proximity and shared culture, or a territorial model of ethnic identity. Kazaks and Uzbeks respectively represent examples of these two models. Processes of ethnic demarcation have, however, been greatly accelerated during the Soviet period and its aftermath. Today, a hasty search for national identities can be observed across the region; while following lines of Soviet ethnicity concepts, these identities fundamentally change their understanding as well as inter-ethnic and majority-minority relations. This is still a very open and dynamic process leading to new (inter-)ethnic constellations and political power relations.