The removal of Indigenous children from their communities to residential schools was a feature of government policy in the settler states of Canada, the USA, Australia, and New Zealand in the late nineteenth and much of the twentieth centuries. The purpose of these institutions was to assimilate their inmates into Euro-colonial society. The architectural strategies used in administering these policies of assimilation are a crucial but often overlooked aspect of systems of colonization. In this paper, I draw connections among these architectures in four countries descended from the British Empire by examining them as “quotations” of one another—linked through direct simulation such as Canada’s use of American boarding schools as a model, or less direct links like the influence of global actors such as missionary organizations or their shared use of Euro-colonial institutional models. Focusing on four case studies—the Mohawk Institute in Canada, Carlisle Indian Industrial School in the USA, Moore River Native Settlement in Australia, and St. Stephen’s College in New Zealand—I read each through the way its architecture functioned as an ideological tool of control in the context of settler-Indigenous relations. The case studies act as indices towards a comparative framework for the spatial products of colonialism, the aim being to describe the significance of architecture and other forms of spatial organization in facilitating parallel colonizing practices around the globe. Finally, I explore the transformation of these built environments over time, demonstrating how changes reflected settler priorities and not those of the Indigenous peoples they affected, and uncovering ruptures between past and present in the complex histories and memories of (post)colonial societies.