Educational communication with peers and teachers has a significant impact on all sides of the school adaptation of younger adolescents. Difficulties in educational communication can be a significant cause of problems of school adaptation. The purpose of this article is to identify and describe the school adaptation problems of adolescents with educational communication difficulties, to study the assessment of these problems by middle school teachers. The article clarifies socially vulnerable groups of young adolescents with a high risk of educational communication difficulties: with behavioral or emotional disorders, with limited health capacities and with disabilities, in a difficult life situation, refugee children, migrants and foreigners, gifted and talented students. Their school adaptation problems are classified into social, communicative, psychological, motivational and academic. The results of the teacher assessment of the prevalence of such problems and difficulties of educational communication in socially vulnerable and socially well-off groups of adolescents were presented. The evaluation was carried out through surveying 53 teachers of Gymnasium 25 of Krasnodar. They assessed the prevalence of problems of school adaptation and educational communication difficulties among 148 students of the 5th grade. The results showed that the most frequent school adaptation problems were noted among adolescents with behavioral and emotional disorders (problems of building relationships with teachers and peers, low educational motivation, self-organization problems), migrants and foreigners (problems with compliance with school norms and rules and mastering the curriculum), teenagers in difficult life situations (problems in building relationships with teachers and classmates, high level of anxiety, low self-esteem). The least frequent problems of school adaptation are found among gifted and talented children (lower than those of normally developing peers). The prevalence of communication difficulties among certain socially vulnerable and socially advantageous groups of adolescents was assessed by teachers in much the same way as the prevalence of school adaptation problems, suggesting a correlation between them.