The article examines the meaning of the concept of "extremism", reveals its illegal essence, signs and causes of its occurrence, and also outlines the lack of a legal definition of the concept of "extremism" in the legislation of Ukraine. The author emphasizes the organizational and legal principles of combating extremism and substantiates the opinion that the main source of extremism is the crisis state of society. A description of the types of extremism and its main forms and consequences for society is given. Thus, among the main forms of extremism we distinguish: production, storage or distribution of extremist materials (inscriptions, leaflets, audiovisual and other materials), use of Internet resources for extremist activities; public statements of extremist content; public appeals or incitement to commit extremist actsfinancing of extremist actions or other assistance in their organization, preparation and implementation, including by providing financial funds, real estate, educational, printing and material-technical base, telephone, fax and other types of communication, as well as providing information services. Derivatives of extremism are singled out, in particular: terrorism, collaborationism, separatism. The characteristics of subjects fighting extremism are presented separately (state authorities and local self-government bodies that participate within their competence; the Security Service of Ukraine and the State Bureau of Investigation, if representatives of authorities participate in extremist activities), as well as the content of the main directions of combating it. Prospective directions for further scientific research are the study of the experience of the countries of the European Union in countering extremism, the current state of countering extremism in Ukraine, and ways to improve the domestic legislation.

Розглянуто поняття екстремізму, його антиправову сутність, ознаки та причини виникнення. Акцентовано увагу на організаційно-правових засадах протидії екстремізму. Обґрунтовано думку, що основним джерелом екстремізму є кризовий стан суспільства. Подано характеристику різновидів екстремізму. Визначено наслідки екстремізму та шляхи протидії його проявам.