Militant Muslim terrorist group based in Indonesia. They are most infamously known for the October 12 2002 bombing of two nightclubs in Kuta Beach, Bali that killed 202 people, mostly Australian tourists and Indonesian locals. The group has also been implicated with bombings against several Christian churches around Christmas 2000, and (probably) the Marriott Hotel in Jakarta on 6 August 2003, and had planned to mount terrorist attacks against Singapore, and an APEC conference in Bangkok.

Abu Bakar Bashir is considered to be the organisation's spiritual leader. He has an odd resemblance to a swarthy but frail Colonel Saunders. From around 1969 he and a motley group of purists was promoting Darul Islam, a more extreme form of Islam to fight modernity that was encroaching on South East Asia. His actions, while just limited to running religious schools and a pirate radio station, were naturally of concern to the secularist authoritarian regime of Suharto, who had Bashir arrested and gaoled. Bashir escaped and fled to Malaysia in 1982, where he later met Riduan Isamuddin (aka Hambali), a veteran mujahideen from the Afghan conflict.

JI got back into proselytising and slowly built up a strong team of supporters, while forming links with other terrorist groups including al Qaeda, Abu Sayyaf and the Moro Islamic Liberation Front. In the late 1990s their power base grew following the downfall of the Suharto regime and the democratisation of Indonesian politics. The social turmoil that was created by the Asian Economic Crisis, and the sense of injury generated when Australian forces took control over East Timor as part of a United Nations peacekeeping mission radicalised JI further. Their objective was to create an Islamic superstate comprising of Malaysia, Singapore, Indonesia and the southern Philippines by supporting local Muslim insurgent groups.

In the aftermath of the Bali bombings Bashir was arrested (over the Christmas bombings) and Hambali was captured in Thailand. To this date however there is no conclusive evidence that JI has been disbanded.