The author of the article analyses the potential and risks of pedagogical maintenance of students’ subjective development in the educational environment on the basis of reflectiveenvironmental approach. Subjectivity is seen as an integral quality of a person, which includes activity, reflexivity, awareness, value orientations, and several other subjective properties. Reflexive-environmental approach to building this kind of maintenance is indicated as a possible way to overcome the problems mentioned. Through the use of reflexive mechanisms, it helps to identify and evaluate the conditions of mutual interaction between the subjects and educational environments. The author presents the structure of a reflective portfolio «Development of high-school students’ social activity » as a reflexive mechanism, analyzes its capabilities and limitations in promoting students’ motivation and increasing their level of activity. The main attention is focused on students’ personal involvement into accompanying processes, as well as teacher’s tutoring position - the position of acceptance and recognition of subjectivity of every child. The reasons of limited integrity of pedagogical support of boys and girls are analysed in the article. The author presents the results of the qualitative analysis of senior students’ subjectivity obtained during the conducted research.