This dissertation examines how multiple imperial powers in Chinese treaty port cities interacted during the late nineteenth and early twentieth centuries. It centers on China’s two largest treaty port cities: Tianjin and Shanghai, two cities that were divided into several colonial concessions alongside the Chinese districts from the 1860s to 1940s. Historically, while Shanghai was characterized by its tripartite division of governance—the British-dominated International Settlement, the French Concession, and the Chinese municipality, Tianjin was home to up to nine foreign-controlled concessions (British, American, French, German, Japanese, Russian, Belgian, Austro-Hungarian, and Italian). This dissertation inquires into how these multiple imperialisms shaped, and were shaped by, these two cities. Situated at the intersection of modern Chinese history, empire studies, and urban history, this dissertation investigates how the multi-pronged and multifarious interactions between various imperial powers shaped the urban politics of these two cities, as well as their urban development. While much scholarship on colonial history has focused on the bilateral relationship between the colonizer and the colonized, my research reveals the multiplicity, multilateralism, and multilayered trajectories at the heart of the colonial experiences of both imperial powers and the Chinese. Drawing on a wide range of multi-lingual historical materials located in different parts of the world, this dissertation underscores the density and concentration of crisscrossing imperial trajectories within cities while situating Chinese colonial history within a global comparative framework.