ASEAN (the Association of South-east Asian Nations). Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand.
ASEAN + 3 (APT). The above plus China, South Korea, Japan.
East Asia Summit (EAS). ASEAN + 3, together with Australia, India, New Zealand, Russia and one observer.
ASEAN Regional Forum (ARF). Australia, Bangladesh, Brunei, Cambodia, Canada, China, East Timor, EU, Indonesia, Japan, Malaysia, Myanmar, Mongolia, New Zealand, North Korea, Pakistan, Papua New Guinea, Philippines, Russia, Singapore, South Korea, Sri Lanka, Thailand, US, Vietnam.
Asia-Pacific Economic Cooperation (APEC). Australia, Brunei, Canada, Chile, China, Chinese Taipei, Hong Kong, Indonesia, Japan, Malaysia, Mexico, New Zealand, Papua New Guinea, Peru, the Philippines, Russia, Singapore, South Korea, Thailand, US, Vietnam.
Shanghai Cooperation Organisation (SCO). China, Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan. India, Iran, Pakistan and Mongolia have observer status.