This thesis investigates the fundamental social, cultural, demographic, economic and political changes that precipitated and encouraged the first significant wave of multiple-occupancy dwelling in Brisbane: the residential flats of the interwar period of the twentieth century. Brisbane’s earliest ‘flats’ had emerged by the 1910s, the product of converting large, obsolete nineteenth-century residences into multiple dwellings. Often not fully self-contained, they differed only marginally from the traditional rooming-house, and were widely considered as a short-term expedient in the face of a severe housing shortage. In the 1920s Brisbane residents were introduced to the purpose-designed, modern urban flat. Acceptance was gradual, but by the second half of the 1930s, new flat construction in Brisbane was booming. The emergence of the purpose-built flat represented, physically and culturally, the city’s introduction to a distinctively twentieth century, modern lifestyle. The shift to flat-living created: vigorous community debate over the fear of slum creation; formal responses to these concerns in the form of local ordinances controlling the construction and licensing of flat buildings; and substantial change to the character of inner-suburban Brisbane. Defining, accounting for, deriving meaning from, and exploring the significance of, the fashion for flat-dwelling in interwar Brisbane – in particular the popularity of the purpose-designed, purpose-built blocks of flats – are the objectives of this research. The fashion for living in flats in Brisbane is considered within three broad frameworks: the continuity of the urban experience across time and place; the democratisation of modernity and notions of what it meant to be ‘modern’ in Brisbane in the 1920s and 1930s; and the cultural legacy. In pursuing these objectives the study considers contemporary debates about the nature of urban living and the need for town planning initiatives in Queensland; the inter-relationship between the compact flat and the lifestyle it generated; generic profiles of those who occupied and invested in purpose-built flat developments; interwar controls (overt and covert) on new flat construction; and the resultant environmental impact in terms of location, form, scale, materials and neighbourhood character. In conclusion, the cultural value of Brisbane’s interwar flats as a distinctive built form is addressed.