Abstract
As one of the more successful regional organisations in the world, ASEAN has been the driver of regional institution building in the Indo-Pacific. The key features in the ASEAN-led institutions are the informality of these arrangements and the stamp of the ASEAN way in regional processes dealing with security challenges. The article argues that despite changes in the strategic landscape with new challenges like the political crisis in Myanmar, an increasingly belligerent Chinese position on the South China Sea issue, heightened rivalry between the US and China, and a host of transborder non-traditional security threats, informality entrenched in ASEAN way remains the preferred modality in regional security governance. But while informality has had limited success in managing certain regional issues in the past, the pressure for ASEAN to recalibrate its informal processes and make the organization fit-for-purpose to deal with twenty-first century security challenges has become more urgent than ever.