This thesis examines Australian ideas about the Antarctic in the nineteenth and early-twentieth centuries. It seeks to go beyond the dominant diplomatic, geopolitical, legal, and scientific lenses through which Australian engagement with the Antarctic region has been viewed by tracing the genealogy of Australian ideas about the Antarctic. It focuses particularly on the development of the ideas that Australia had a unique interest in the Antarctic based on geographical proximity, that the Antarctic was destined to become an Australian possession, and that it would eventually become a source of enormous wealth for Australia and Australians. These ideas are used to reconstruct late-nineteenth and early-twentieth century visions of an Australian empire stretching “from the equator to the South Pole”, a vision that was substantially fulfilled by the 1930s. The thesis argues that these ideas and visions highlight the significance of expansionism in nineteenth and early-twentieth century Australian thought and suggests that this expansionism can usefully be understood as a form of imperialism. It further argues that analysing Australian engagement with the Antarctic within the framework of empire and imperialism provides a valuable insight into the broader phenomenon of expansion by small, newly-formed, states in this period and into the interrelationship between processes of state formation and imperial expansion.