© 2015, © 2015 Australian Institute of International Affairs. Alliances continue to occupy a prominent place in the Asia-Pacific's security architecture. For many regional states such as Australia and Japan, their respective alliances with the USA are the unchallenged foundations of their security. But when the rise of China is causing major change in the region, and when many countries are increasingly reliant on China economically, is the region's network of alliances any longer appropriate or useful? This article reviews alliances in theory and practice, and argues that, while alliances are unlikely to disappear, their utility is nothing like as clear-cut as many of their supporters would have one believe.