The article presents an overview of the problem of the affective sphere of adolescents on both theoretical and empirical levels. Its relevance and, at the same time, the prospect for further research is justified. It was revealed that the emotional life of persons of pubertal period is differently disclosed in the scientific heritage of foreign scientists, but insufficiently covered in the domestic. Correlations between the emotional experiences of adolescents and their relationships with parents, peers; gender identity; eating disorders, etc., were established. Against the background of emphasizing the influence of various external psychological factors in the life of an adolescent, the topic of the intrapersonal, psychological potential of persons of this age remains open. Taking into account the topicality of the problem of emotional instability of teenagers, we aimed to find out in detail, from an empirical point of view, the internal psychological reasons of this phenomenon. For this purpose, the ascertaining experiment was carried out which involved 300 pupils of 6-7 and 8-9 forms of the general secondary educational institutions of the Ternopil region (Berezhanska Secondary School № 1 and Berezhanska Secondary School № 2). Respondents were offered specific, according to the formulated scientific problem, a package of psychodiagnostic techniques, directed to the research of features of the level of manifestation as well as categories of hypothetical factors of emotional stability of adolescents. The next stage of the study involved processing the data by factor analysis using the capabilities of Microsoft Excel and SPSS 21 software. As a result, 10 psychological factors that cause emotional instability in adolescents were identified. Among them: imbalance of self-esteem and personal abilities, personal insecurity compensated by self-control, low resistance to stress, impulsiveness against insecurity, dissonance in the assessment of one's own self, motivational polarity, emotional uncertainty, public insecurity, uncertainty in own abilities, confident behavior. The prospect of our study is the development and practical implementation of social psychological training as a means of correcting dysregulation of the affective sphere of personality and the development of their emotional stability.