This paper aims to explore the influence of political extremism, which causes the emergence and development of various forms of terrorism. While this is an international problem that manifests itself all over the globe, this phenomenon has not been sufficiently explored, especially not its impact on Islamist terrorism. The paper focuses on the question of how and under what conditions political extremism arises, and how it inspires the emergence of terrorism. Given that political extremism is a form of political action, inevitably a political creation, and only then a security, social, politicological and anthropological phenomenon, the impact it has on political relations is extremely important. Political extremism is a distinctly political phenomenon that can produce immeasurable consequences (it starts with the persecution of opponents and different-minded persons, and ends with atrocities). Terrorism is, in fact, implemented extremism. Religion can be an important and indispensable factor of extremism and terrorism. Although extremism and terrorism may be inspired by extreme interpretation of any religion, it is a statistical fact that the number of terrorist organizations whose ideology is based on Islamic fundamentalism today is much greater than the number of those that are related to other religions.