The Republic of Indonesia (pron-en??ndo??ni?zi? or IPA-en??nd??ni???) (lang-idRepublik Indonesia) is a country in Southeast Asia and Oceania. Indonesia comprises 17,508 islands (List of islands of Indonesia). With a population of around 230 million people, it is the worlds fourth most populous (List of countries by population) country, and has the worlds largest population of Muslims (List of Muslim majority countries). Indonesia is a republic, with an elected legislature and president (President of Indonesia). The nations capital city is Jakarta. The country shares land borders with Papua New Guinea, East Timor, and Malaysia. Other neighboring countries include Singapore, Philippines, Australia (Australia-Indonesia border), and the Indian territory of the Andaman and Nicobar Islands.

The Indonesian archipelago has been an important trade region since at least the seventh century, when Srivijaya and then later Majapahit traded with China and India. Local rulers gradually adopted Indian cultural, religious and political models from the early centuries CE (Common Era), and Hindu (Hinduism in Southeast Asia) and Buddhist (Buddhism) kingdoms flourished. Indonesian history has been influenced by foreign powers drawn to its natural resources. Muslim traders brought Islam, and European powers fought one another to monopolize trade in the Spice Islands of Maluku (Maluku Islands) during the Age of Discovery. Following three and a half centuries of Dutch colonialism (Dutch East Indies), Indonesia secured its independence (Indonesian Declaration of Independence) after World War II. Indonesias history has since been turbulent, with challenges posed by natural disasters, corruption, separatism, a democratization process (Post-Suharto era), and periods of rapid economic change.

Across its many islands, Indonesia consists of distinct ethnic, linguistic, and religious groups. The Javanese (Javanese people) are the largest—and the politically dominant—ethnic group. Indonesia has developed a shared identity defined by a national language (Indonesian language), ethnic diversity, religious pluralism within a majority Muslim population, and a history of colonialism including rebellion against it. Indonesias national motto, "Bhinneka Tunggal Ika" ("Unity in Diversity" literally, "many, yet one"), articulates the diversity that shapes the country. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support the worlds second highest level of biodiversity. The country is richly endowed with natural resources, yet poverty remains widespread in contemporary Indonesia.