The Asia-Pacific region’s rapid growth since the 1950s had been supported by a favourable external economic environment and opportunities arising from globalization. This, however, has changed dramatically in the aftermath of the global financial crisis of 2008-2009. In the new global environment, sustaining the region’s growth and realizing the Asia-Pacific century critically depends on its ability to harness the potential of regional economic integration. In light of the many complementarities arising from its diversity, the region, a late starter in regionalism, has many underexploited opportunities for mutually beneficial regional integration. Regional economic integration can also assist in making regional development more balanced, with the lagging economies receiving a boost through stronger connectivity and integration with economic growth poles, such as China and India. Besides fostering peace, such cooperation could also help the region address shared vulnerabilities and risks and exercise its influence in global economic governance in a way commensurate to its rising economic weight.