FOMO is a relatively new category used to describe phenomena related to the fear of missing out on important news or events from other people’s lives, which may lead to rejection by others. The intense discomfort associated with this anxiety can lead to the development of coping mechanisms, including constant engagement in online activities. As a result of excessive online activity, interpersonal relationships in the real world can be disturbed, and an individual’s quality of life can be significantly reduced. This problem can be significant for teenagers, who maintain most of their relationships online. The presented article provides a theoretical overview of issues related to FOMO. It describes the main symptoms and threats associated with these phenomena. It also consists of a theoretical proposal of preventive activities and the central psychotherapeutic interventions that can be offered to a person suffering from FOMO or at risk of developing it.