This article first briefly outlines the current terrorist threat posed by militant Islamist radical terrorism and the complexity and evolving nature of threat. It highlights the lack of consensus in academic and policy communities regarding the underlying causes of this terrorism. It them posits that the overarching challenge in the next few years will be to maintain the broad-based international co-operation in the fight against terrorism that has existed since 11 September 2001, which is essential to address the threat effectively. Elements of this challenge include dispelling the notion that the US-led counterterrorism effort is targeting Islam and keeping the global South engaged. Durable, effective and flexible mechanisms are needed at the global, regional and national levels to ensure that multifaceted, holistic strategies are developed and implemented to address these issues. The article then outlines the current capacity of multilateral institutions to contribute to the fight against terrorism. The performance of the main UN counterterrorism bodies – led by the Security Council’s different counterterrorism entities – as well as some of the key regional and functional ones, this article concludes, has been uneven. Different organisations have developed counterterrorism programs and units, but these have emerged from political reactions rather than strategic decisions with corresponding achievable technical objectives. The duplication of efforts, overlapping mandates and lack of co-ordination at the international, regional and sub-regional levels have limited the different bodies’ overall contribution to the global non-military counterterrorism effort and have left many of the world’s vulnerabilities to terrorism unaddressed. This article concludes that maintaining international co-operation and the focus on capacity-building and other non-military counterterrorism measures, as well as the need to address the proliferation of counterterrorism bodies, highlights the need for an effective multilateral body at the center of the effort. The UN Security Council’s Counter-Terrorism Committee was supposed to be this body, but it has been unable to fulfill its broad mandate effectively. The article details the limitations of the current UN Security Council-led approach and the inherent, political, administrative and budgetary challenges of operating within the UN system that would make it difficult to co-ordinate global capacity-building efforts effectively. While it proposes a possible short-term improvement – the consolidation of the different parts of the Security Council counterterrorism program into as single body – in the end, it argues that a new international body dedicated to counterterrorism outside of, but perhaps related in some way to, the UN may be needed.