War and military practices have shaped and reshaped cities and suburbia for millennia. Concentrated settlements hidden behind high walls were an important pattern of defence at a time before planes and aerial warfare. From the early twentieth century, decentralized settlements and urban deconcentration have provided better protection against military attacks. The Japanese military developed suburban settlements in the 1930s knowing the potential danger of wars fought in the dense cities mostly built out of wood. Modernist planners in post-war Germany proposed high-rise buildings in greenery, based on their experience of firestorms created by bombs and rubble that blocked streets. In the US, the defence industry was an integral part of the national suburbanization process. During WWII, the Mutual Ownership Defense Housing Division promoted the construction of suburban housing projects for defence workers and their families. Post-war suburbanization was fuelled by discharged veterans, while German-based US military housing settlements became a way to apply American ideals to the Cold War’s easternmost frontier. In Israel, American-style suburbs housing acting military officers formed a governmental tool to stimulate the development of peripheral towns and to facilitate territorial expansion. In conclusion, this chapter reflects on modern warfare in the design of contemporary cities.