One sector of work that is growing rapidly as well as high potential for the issue of work stress is the banking industry. This can be triggered by a lot of workload and is always changing at any time or monotonous work. Increased work overload and other factors can also cause work stress and inconvenience for employees so that it disrupts their performance. In addition, work stress can be caused by work family conflict in employees. Work family conflict and work stress often arise when one of the roles at work demands more or requires more attention than the role of the family. To overcome this, employees need a form of social support that can come from superiors, coworkers, and families so that later these employees can manage their work stress well. The population of this study in Employees at PT. Bank Negara Indonesia Tbk., Branch of Universitas Sumatera Utara, amounting to 143 people. The Slovin formula is used to determine the number of samples, so that a sample of 106 people is obtained. The data analysis method is structural equation modeling-partial least squares (SEM-PLS). The results showed that work overload had a positive and significant effect on work stress, work family conflict had a positive and significant effect on work stress, family social support had a negative and significant effect on work stress, family social support had a significant effect in moderating between work overload on work stress, and family social support do not have a significant effect in moderating between work family conflicts with work stress.