This paper presents initial findings from longer-term transdisciplinary research concerning the social dynamics of urban neighbourhoods. It examines the spatial clustering of ethnicity and class in neighbourhoods over urban history, from Bronze Age Mesopotamia to contemporary cities. Fourteen distinct drivers of social clustering are identified, grouped under the headers of macro-structural forces, the state, local regimes and institutions, and bottom-up processes. The operation of these processes is examined through three historical and three archaeological case studies of clustering.