The urgency to study the reasons of inter-ethnic conflicts in educational institutions is connected to insufficient knowledge on the psychological and pedagogical causes of children and students' aggressive behavior, leading to the importance to disclose the conditions, mechanisms, means of its correction and prevention taking into account interethnic relations. The purpose of the paper is to reveal the peculiarities of children and students' aggressive behavior studying in classes and groups with different poly-ethnic composition and, on this basis, to develop the areas of application of mediation technologies for solving interethnic conflicts among students in conditions of a multiethnic educational environment. The author defines the main types, forms and features of aggressive behavior manifestation among students in poly-ethnic groups. The directions of mediation technologies application for interethnic conflicts prevention are proposed in conditions of the educational organization, where a special role belongs to the ethno-mediation, as a way of settling interethnic relations, the prevention of radical ideologies in a poly-ethnic educational environment. © 2018.