This article examines why Asia’s multilateral defence diplomacy has been a relative laggard when compared to other forms of institutionalized security dialogue, and what explains its recent rise. It argues that explanations that stress the “catalytic role” of external shocks such as the Asian Financial Crisis (AFC) or changes in the distribution of power or threats are underdetermining. Rather, Asia’s new multilateral defence diplomacy reflects strategic emulation on the part of ASEAN elites, who localized ideas initially put forward by outsiders in order to maintain ASEAN’s central place in the regional security architecture. Its rise has also been helped by the changing role of militaries in some East Asian states and its rapid institutionalization owes much to historical contingency, in particular the interests of two influential ASEAN Chairs in Indonesia and Vietnam. The final part of the article briefly assesses the future prospects and influence of regional multilateral defence diplomacy.