The aim of the article is to identify the main directions of activities of organizations (the UN, the European Union, the League of Arab States (LAS) and the Organization of Islamic Cooperation (OIC)) aimed at reducing the radicalization process, influencing the development of extremism and terrorism. In order to achieve the set objective, the main method in the study was document analysis. We have summarized the different concepts and models of radicalization highlighted by researchers in their works. This allowed us to better present the causes of radicalization, and to systematize the normative framework that addresses the activities of organizations (the UN, the European Union, the League of Arab States (LAS) and the Organization of Islamic Cooperation (OIC) in the field of preventing and combating international terrorism. The authors conclude that the evolution of the activities of international organizations can be described as a radical change in the views of the international community in the 21st century on international terrorism. What used to be considered a phenomenon that was at times perceived as important, but definitely not a central or serious strategic problem, now, in fact, has the rank of an existential threat to international peace and security. At the same time, there are many unresolved problems that complicate international co-operation. There are still fundamental differences among States in defining terrorism, rooted in their ideologies, historical experiences, interests, prejudices and lack of trust.