Adopting an analytically eclectic approach that draws on theories of realist bargaining, identity, and socialization, this article investigates the early Cold War origins of the Five Eyes intelligence grouping (the United States, Canada, Great Britain, Australia, and New Zealand). An understanding of identity grounded in culture suggests a natural process of international intelligence community building, but this was not the case with the Five Eyes. The formation of the grouping was not preordained. Although Anglo-Saxonism was a necessary condition, it was not sufficient. In addition to being able to provide valuable sites for signals intelligence collection, aspiring members had to be seen as staunchly anti-Communist (and therefore politically trustworthy) by the United States in order to become full members of this exclusive community. Early postwar concerns over the political loyalties and secrecy protection regime of the Australian government prompted the British to initiate a process of socialization aimed at bolstering its affiliate's security institutions and practices and guaranteeing its own access to U.S. secrets.