Australia’s relationship with Indonesia has been a topic in diplomatic, academic, defence and intelligence circles in Australia for over fifty years. Australian diplomacy towards Indonesia in the period from the attempted coup in October 1965 until the fall of the Liberal – Country Party coalition in 1972, remains relatively overlooked by Australian researchers. There is virtually no research of this period drawn from Australian archival sources. This thesis seeks to rectify this gap in our knowledge. The study suggests that Australian diplomacy towards Indonesia from 1965 to 1972 was dominated by a fear which contradicted Australian intelligence and defence assessments of Indonesia’s threat potential to Australia. This study will examine how this fear contributed to, and was also reinforced by, a lack of a clear working definition of what constituted ‘security’ in an Australian context. It bred a sense of insecurity and vulnerability by which Australian policy makers departed from a course of rationality. This is reflected in Australian relations with the New Order Government which were dominated by strategic concerns. Although Australia desired an informal closeness to the New Order Government, Jakarta’s increasing repression exposed Australia to international and domestic opprobrium with regard to the more salient abuses of the New Order Government. / Doctor of Philosophy (PhD)