Studies looking at many aspects of SNS addiction have dramatically increased in recent years. Most of the SNS addiction research has focused on individual behaviors. There is little academic research about SNS addiction in the workplace. This study, therefore, plans to examine the organizational behaviors related to SNS addiction in the workplace. We investigate whether negative behaviors in the workplace induce SNS addiction, and how SNS addiction influences the organizational or social attitudes of employees. We also explore the possible mediating effect of SNS addiction. We use an online survey and collected 285 responses from office workers in South Korea. The results tested by a structural equation modeling indicate, first, that both abusive supervision and workplace bullying have aroused SNS addiction among employees; second, employees’ SNS addiction increases both from work-to-family-conflicts and family-to-work-conflicts; and third, SNS addiction fully mediates the relationship between abusive supervision and workplace bullying, as well as the relationship among abusive supervision, workplace bullying, and work-family conflicts. The study finds that abusive supervision and workplace bullying are important antecedents of SNS addiction, and that SNS addiction affects conflicts in both work-to-family and family-to-work situations. Therefore, companies should be cognizant of potential mediating influences in monitoring employees’ SNS usage in order to improve their work environments.