Indonesia (/ˌɪndəˈniːʒə/ (listen) IN-də-NEE-zhə, /-ˈniːziə/ -⁠NEE-zee-ə; Indonesian: [ɪndoˈnesia]), officially the Republic of Indonesia (Indonesian: Republik Indonesia [reˈpublik ɪndoˈnesia]), is a country in Southeast Asia, between the Indian and Pacific oceans. It is the world's largest island country, with more than seventeen thousand islands,^[11] and at 1,904,569 square kilometres (735,358 square miles), the 14th largest by land area and the 7th largest in combined sea and land area.^[12] With over 261 million people, it is the world's 4th most populous country as well as the most populous Muslim-majority country.^[13] Java, the world's most populous island,^[14] contains more than half of the country's population.

The sovereign state is a presidential, constitutional republic with an elected parliament. It has 34 provinces, of which five have special status. Jakarta, the country's capital, is the second most populous urban area in the world. The country shares land borders with Papua New Guinea, East Timor, and the eastern part of Malaysia. Other neighbouring countries include Singapore, Vietnam, the Philippines, Australia, Palau, Thailand, and India's Andaman and Nicobar Islands. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support a high level of biodiversity.^[15] The country has abundant natural resources like oil and natural gas, tin, copper and gold. Agriculture mainly produces rice, palm oil, tea, coffee, cacao, medicinal plants, spices and rubber.^[16] Indonesia's major trading partners are China, United States, Japan, Singapore and India.^[17]

History of the Indonesian archipelago has been influenced by foreign powers drawn to its natural resources. It has been an important region for trade since at least the 7th century, when Srivijaya and then later Majapahit traded with entities from mainland China and the Indian subcontinent. Local rulers gradually absorbed foreign cultural, religious and political models from the early centuries and Hindu and Buddhist kingdoms flourished. Muslim traders and Sufi scholars brought Islam,^[18][19] while European powers brought Christianity and fought one another to monopolise trade in the Spice Islands of Maluku during the Age of Discovery. Although sometimes interrupted by the Portuguese, French and British, the Dutch were the foremost European power for much of its 350-year presence in the archipelago. In early 20th century, the concept of "Indonesia" as a nation state emerged, and independence movements began to take shape.^[20]During the decolonisation of Asia after World War II, Indonesia achieved independence in 1949 following an armed and diplomatic conflict with the Netherlands.

Indonesia consists of hundreds of distinct native ethnic and linguistic groups, with the largest—and politically dominant—ethnic group being the Javanese. A shared identity has developed, defined by a national language, ethnic diversity, religious pluralism within a Muslim-majority population, and a history of colonialism and rebellion against it. Indonesia's national motto, "Bhinneka Tunggal Ika" ("Unity in Diversity" literally, "many, yet one"), articulates the diversity that shapes the country. Indonesia's economy is the world's 16thlargest by nominal GDP and the 7th largest by GDP at PPP. Indonesia is a member of several multilateral organisations, including the UN,^[a] WTO, IMF and G20. It is also a founding member of Non-Aligned Movement, Association of Southeast Asian Nations, Asia-Pacific Economic Cooperation, East Asia Summit, Asian Infrastructure Investment Bank and Organisation of Islamic Cooperation.