The article deals with the issue of ethnic identity and forms of its manifestation in Ukrainian school students. The essence of the concepts of "ethnic identity", "group", "nation", "ethnic groups" as well as the difference between these notions are revealed and described. Scientific works of some researches concerning this issue are reviewed. The ideas of Austrian scientists R. Sprenger and O. Bauer about the national character as the most important attribute of nation are considered. The results of the psycho-diagnostic techniques aimed at revealing personal identity, ethnic self-consciousness and its transformations in terms of inter-ethnic interaction, the level of native speaker's competency, revealing the attitude towards other nationalities, value orientations in inter-ethnic interaction are presented and considered. The projective technique "I am a representative of my nation" shows the way ethnic identity is manifested in each respondent. The used techniques also reveal the importance of the influence of political and economic situation in a country on the formation of ethnic identity of adolescents. The results of the carried out research are presented in tables in percentage ratio. According to the obtained results, the formation of ethnic identity takes place at the age of 15-16 years. The most of the surveyed have positive ethnic identity, which is a standard typical for a multi-ethnic society. All the respondents have a good command of the native language and use it in their everyday communication. Most of the examinees feel their belonging to a certain ethnic society, but 18,27% of school students don't have this feeling. This result is also confirmed due to the projective drawing test, which showed that 14,74% of adolescents do not identify themselves with their ethnic group. The investigation has also shown the aggressive emotions of the surveyed (35,28%) and massage of peace (26,46%), which speaks for the impact of the political situation in the country on adolescents' psychological state. Despite this fact, it helps them to think of the national unity and integrity, as well as the necessity to respect other nationalities. The carried out researches have revealed the level of ethnic identity, and the obtained results allow to conduct psycho-correctional, developmental and training activity with school students.