In this article the ambivalence of public policy responses to diversity on the street are documented empirically through a detailed case study of the marginalization of youth from the downtown public spaces of Portland, Maine, USA. Urban planners, architects and property developers have become increasingly concerned with improving the quality of urban life and the public spaces on which it depends. They argue that urban revitalization initiatives must embrace diversity — cultural and economic, as well as functional and spatial. This diversity of different ‘diversities’ is often under‐theorized, as are the benefits of, and relationships among, social and cultural diversity, economic diversification, mixed‐use and multi‐purpose zoning, political pluralism, and democratic public space. It is my contention that this ambivalence is not simply a smokescreen for vested commercial interests, but also provides opportunities for expressing alternative visions of what diversity and the city itself should be. Looking specifically at youth, I explore a relatively underexamined aspect of inner‐city diversity. While there is a relatively well‐developed literature about the contested place of low‐income groups, racial minorities and the homeless in urban redevelopment initiatives, youth have largely been ignored.