The article is devoted to the relevance of the psychological and pedagogical substantiation to the study of professional self-determination of high school students. Taking into account  a rapidly developing post-industrial society, the problems of personality formation based on the individual capabilities and needs of the student and the identification of the trajectory of professional self-determination are reflected in the continuous pedagogical process. To increase the effectiveness of this process, especially for a student who wants to enter adulthood, psychological and pedagogical support is needed not only in choosing a profession, but also in finding resources to develop and implement his educational and professional scenario, contributing to the independent use of these resources in the learning process. In this regard, one of the main tasks of the secondary school is to provide psychological and pedagogical support to students in professional self-determination and determination of attitudes in step-by-step decision-making on the continuation and further professionalization of education.

The purpose of the study: psychological and pedagogical substantiation of the study of the level of professional self-determination of high school students.

During the research, the authors used methods of theoretical analysis and empirical processing of psychological and pedagogical data, diagnostics, scientific analysis of the concepts of "profession", "career guidance", "professional self-determination", etc. The conducted scientific and theoretical analysis allowed to substantiate approaches to the diagnosis of psychological and pedagogical features of the level of professional self-determination of students. The article provides a justification for the diagnosis of professional self-determination of high school students in secondary education organizations when choosing the profession of "Teacher" from a psychological and pedagogical point of view.