The article substantiates the importance of the activities of the class teacher for the diagnosis and socialization of children from disadvantaged families. Along with the main pedagogical activity, the class teacher carries out activities for the adaptation and socialization of children, interacting with the family, ensuring the solution of key tasks and solving issues of child upbringing. The main goals and objectives that the class teacher sets and solves for himself imply effective and regular interaction with the microsocium: parents, students, teachers, social educators and psychologists. The purpose of the article is to reveal the significance of the activities of the class teacher for the diagnosis and socialization of children from disadvantaged families, to show the directions of this activity in a mass school. The methodological basis of the article was the work of such authors as S. A. Belicheva, O. I. Volzhina, A. A. Rean, M. I. Rozhkov, V. M. Tseluiko, T. I. Shulga and others. The study is based on an activity approach, which sets the benchmark for including the child in a variety of areas of emotionally rich socially recognized and socially approved activities.