The concept of solidarity and related policies and practices are central to many urban initiatives throughout the global north that support vulnerable migrants and refugees. In this paper, I unpack various meanings of the concept of solidarity within urban migrant- and refugee-supporting initiatives and campaigns. Drawing on expert interviews with activists, community leaders, and municipal administrators and politicians in Berlin and Freiburg, Germany, and Zurich, Switzerland, I show the complexity and contradictory manner in which urban solidarity is understood and practiced. While urban solidarity may appeal to a wide political spectrum and incorporate top–down policies and bottom–up practices and approaches, urban actors also embrace various terminologies, such as Solidarity City and urban citizenship, in response to local circumstances and political strategies.