I. All 11 Countries of Southeast Asia

1. Vietnam, Laos, Cambodia, Thailand, Myanmar (5 Mainland Southeast Asian / Indochina Peninsula Countries)

2. Malaysia, Singapore, Brunei, Indonesia, Philippines (5 Malay Archipelago Countries)

3. Timor-Leste (Newly Established Sovereign State in Southeast Asia)

II. Official ASEAN Member States (10 Countries)

Vietnam, Laos, Cambodia, Thailand, Myanmar, Malaysia, Singapore, Brunei, Indonesia, Philippines

III. Regional Studies Subdivisions

• Indochina Peninsula (Continental Southeast Asia): Vietnam, Laos, Cambodia, Thailand, Myanmar

• Maritime / Archipelagic Southeast Asia: Singapore, Malaysia, Brunei, Indonesia, Philippines, Timor-Leste