The militant jihadi movement has been growing steadily in Malaysia since the early 1970s. The origins of Jemaah Islamiyah (JI) can be traced to Seremban, Malaysia, where Abu Bakar Ba‘asyir began laying the groundwork for the organization in the early 1980s. When he spearheaded the formal establishment of JI a decade later, Ba‘asyir created four mantiqis (bases) covering Malaysia and Singapore, Thailand and the Philippines, Indonesia and Sulawesi, and Australia and the Papuas. JI went on to serve as a platform for international terrorist groups. Al-Qa‘ida and, more recently, the Islamic State (ISIS) have tapped into JI’s organizational structure in order to increase their influence in Southeast Asia. This essay explores this ongoing synergy between regional and international militant groups in Malaysia, and examines the government’s continued failure to contain the spread of extremism.