Australia's experience of the International Geophysical Year (IGY) in Antarctica (1957–8) tempers the dominant narrative of the IGY as a transformative event in Antarctic affairs. This article argues that the IGY was not a great rupture in Australia's relationship with Antarctica. Rather, because of a long cultural attachment to and continuing relationship with Antarctica based in concepts of national security and development, Australian government policy stubbornly adhered to the idea of territorial sovereignty. Recognising this continuity in Australia's relationship with Antarctica is important for reconfiguring our understanding of how the Antarctic Treaty took the form it did.