How can one understand the increasing interest in “urban invasions”, or biological invasions in urban environments? We argue that interest in urban invasions echoes a broader evolution in how ecologists view “the city” in relation to “the natural”. Previously stark categorical distinctions between urban and natural, human and wild, city and ecology have foundered. Drawing on conceptual material and an analysis of key texts, we first show how the ecological sciences in general – and then invasion science in particular – previously had a blind spot for cities, despite a number of important historical and continental European exceptions. Then, we document the advent of an urban turn in ecology and, more recently, in invasion ecology, and how this has challenged fundamental concepts about “nativity”, “naturalness”, and human agency in nature. The urban turn necessitates more explicit and direct attention to human roles and judgements. Ecology has moved from contempt (or indifference) for cities, towards interest or even sympathy.