This chapter explores the Organization of Islamic Cooperation's (OIC) response to ISIL terrorism. It examines OIC's capacity to contribute to state and human security, and shows some mechanisms for counter-terrorism. The chapter argues that, although the OIC is in the process of expanding its institutional reach and has prioritized counter-terrorism in recent years, it has limited capacity to adequately address extremist groups in member states. The OIC has provided humanitarian assistance since the onset of war in Syria, working with and through various UN agencies to assess and meet the needs of civilians in Syria and of refugees in neighboring countries. In fact, the secretaries-general of the OIC, LAS and GCC have held several high-level meetings to address the crisis in the Middle East. Though the Syrian crisis has received more attention, the OIC also has addressed the humanitarian crisis in Iraq, ISIL's place of origin.