The aim of this study was to investigate the moderating role of individual (gender, age, education), and occupational (employment duration, workplace position, the duration of negative behaviour, and the number of perpetrators) characteristics of victims and perpetrators of negative workplace behaviours in the relationship between workplace bullying and mental health. On the basis of the study on a sample of 904 employees, it was possible to determine the moderating factors. Protective factors contributing to the maintenance of mental health despite experiencing negative workplace behaviours were (a) male sex, (b) a relatively young age, (c) shorter length of job seniority, and (d) postsecondary education or lower. However, it was adverse for the mental health if negative behaviours were exhibited by a superior and when an employee was convinced that there were several perpetrators.