Indonesia During the Second World War, Japan conquered the so-called Netherlands Indies in present-day Indonesia. After the Japanese surrender in 1945, the Dutch moved to reclaim its colonies which led to an extra-state conflict that ended with Indonesian independence in 1949.

Indonesia is an archipelago with more than 17 000 islands inhabited by a culturally diverse population, which have influenced much of the conflict history of the country. By the time of independence, the borders of the new state were unclear as the political elite in the independent country claimed some territories which had not been controlled by the Dutch, while several local leaders rejected the Indonesian concept and sought self-rule.

The expansionist policies of Indonesia became more proclaimed over time and eventually led to interstate conflict in 1962 against the Netherlands, which at the time controlled territory in the western part of the island New Guinea. Another interstate conflict took place between Indonesia and Malaysia 1963-66.

Internally, the Indonesian government was challenged by Islamic movements as well as breakaway factions from the armed forces, leading to intrastate conflict over government in 1953, and 1958-61. The country also experienced several intrastate conflicts over territory, starting in South Moluccas in 1950, and eventually followed by on-and off fighting in West Papua in 1965-78, in the former Portuguese colony of East Timor in 1975-89, 1992, 97-98, and in the territory of Aceh in 1990-91 and 1999-05. During the second episode of the conflict in Aceh, the rebel group GAM (Gerakan Aceh Merdeka, Free Aceh Movement), employed one-sided violence.

The military had since independence been closely involved in the governance of the country and it strengthened its hold after the self-proclaimed president-for-life Sukarno was replaced by a military-political bureaucracy led by Suharto in 1965-66. The government of Indonesia, including several militias formed by different parts of the armed forces, employed one-sided violence in the context of its intrastate conflicts but also to suppress opposition movements. Large-scale public protests in 1998 eventually led to Suharto's forced resignation and the imposition of democratic rule.

Opposition to the military government and its strong links to the USA led to underground organisations promoting the idea of an Islamic state in Southeast Asia. These groups were the precursors to the Jemaah Islamiah that used one-sided violence on the island of Bali in 2002 targeting the tourism industry.

Since 1946 Indonesia has experienced the extra-state, interstate, intrastate, non-state and one-sided categories of UCDP organised violence.