Hailed for their pragmatism, innovativeness and progressive views, cities and their networks seem to bring a fresh air in current migration debates. Our intent, in this special issue, is to address the scale and significance of this trend by contributing to a greater understanding of their networking activities. Revisiting the conceptual framework used in the literature to date, it addresses the diverse forms of networks, their drivers, internal operation and the functions they perform, at all levels of governance. This introductory paper starts with a review of the scholarship on migration-related city networks. From there, we draw a more fine-grained sense of the ambivalent role of city networks in the design and implementation of migration governance. The final part of this introduction introduces the papers included in this issue, pointing to the ways in which each casts significant new light on these aspects which, in the current literature, remain unresolved.