This study aimed to investigate the effect of workplace bullying (work-related bullying - interpersonal bullying - physical intimidation) on job performance, as well as to examine the mediating role of workplace social support in this relationship. A questionnaire was distributed to a sample of nurses in Egyptian hospitals. Correlations and hieratical correlation analysis were applied to the test hypotheses. The results indicated that bullying related to work has a negative but not significant relationship with job performance, while bullying related to people and physical intimidation has a significant negative relationship with job performance. The results also confirmed the moderate effect of social support in the workplace on the relationship between dimensions of bullying and job performance. Except for the physical intimidation dimension. Many suggestions and recommendations have been presented to reduce bullying in the workplace and mitigate its negative consequences on bullying victims.