The article considers the relationship between the cyber socialization engagement and the Dark Tetrad of personality (Machiavellianism, narcissism, psychopathy, and sadism). The cyber socialization engagement was understood, according to the author’s concept, as having constructive and destructive components. The study purpose was to identify correlation and deterministic relationships between indicators of the cyber socialization engagement and the Dark Tetrad among young university students. The sample included 424 students from Russian universities. For measurements, «The cyber socialization engagement questionnaire» and «The Short Dark Tetrad Scale» were used. It has been established that the relationship between the indicators of the cyber socialization engagement and the Dark Tetrad has a qualitatively heterogeneous character – from the complete absence of connections to mutual determination. The strongest mutual determination is associated with the everyday sadism: it increases the destructive engagement in cyber socialization, explaining 12% of the total variance, and the latter, in turn, increases the severity of sadism (10.5%). It is advisable to take into account the revealed connections between the general cyber socialization engagement and the Dark Tetrad of the personality when organizing psychological support for the socialization of students in the context of expanding social interactions carried out in cyberspace.