Australia is a suburban nation. Today, with increasing concern regarding the sustainability of cities, an appreciation of the complexities of Australian suburbia is critical to the debate about urban futures. As a built environment and a cultural phenomenon, the Australian suburbs have inspired considerable scholarly literature. Yet to date, such scholarly work has largely overlooked the changing environmental values and visions of those shaping and residing within suburban landscapes, and the practices through which such values and visions are materialised in the processes of suburban development. Focusing on the post-war suburban landscapes of Canberra and Perth, this thesis centralises the environmental, political and economic forces that have shaped human action to construct suburban spaces, paying particular attention to the extent to which individual understandings and visions of 'environment' have determined the shape and nature of suburban development. Specifically, it examines how those operating within Australia’s suburbs, including planners, developers, builders, landscape designers and residents have imagined the 'environment', and how such imaginaries have shifted in response to varying spatial, temporal and ideological contexts. Tracing the shifting nature of environmental concern throughout the mid-to-late twentieth century, it argues that despite the somewhat unsustainable nature of Australia's suburban landscapes, the planning and development of such landscapes has long been influenced by and has responded to differing understandings of 'environment', which themselves are the product of changing social, political and economic concerns. In doing so, this thesis challenges a number of perceptions concerning Australian suburbs, environmental awareness and sustainability. In particular, it contests the assumption that environmental concern for Australia's suburban development emerged with the urban consolidation debates of the 1980s and 1990s, and analyses a range of environmental sensibilities not often acknowledged in current histories of Australian environmentalism. By examining, for example, how the deterministic and economic concerns of differing planning bodies, along with the aesthetic and ecological concerns of various planners, are intertwined with the housing and domestic lifestyle preferences of suburban homeowners, this history brings to the fore the often conflicting environmental ideas and practices that arise in the course of suburban development, and provides a more nuanced history of the diversity of environmental sensibilities. In sum, this thesis enhances our understandings of the changing nature of environmental concern and illuminates the complex, still largely misunderstood, environmental ideas and practices that arise in the processes of suburban development.