The article deals with the problem of finding an effective criterion-diagnostic toolkit for assessing of formation of safe social behaviour of college students. The theoretical analysis of pedagogical research on the problem under consideration is presented. As methodological approaches are axiological, dialogical, systemic, on which the author's strategy of development of the toolkit and the nature of interaction with students in the process of diagnostics are based. The necessity of scientific substantiation and theoretical understanding of criteria for the organisation of students' diagnostics is actualized. The focus is on the substantive description of methods for assessing the formation of safe social behaviour. The author's questionnaire, the board game ‟You are not alone”, a set of case tasks, the exercise ‟Ladder of socially safe actions” are developed and proposed, their advantages are noted. To validate the methods used, it is recommended to use expert assessments of parents (legal representatives), specialists of the educational department of the educational organisation, tutors of study groups and clarifying methods (analysis of the products of activity micro-essays, students' stories with elements of reflection, compilation of synquaines, exercise ‟Continue the sentence”).The conclusions about the importance of identifying criteria and searching for diagnostic tools to determine the level and individual characterization of the formation of safe social behavior are made in the conclusion.