Research on abusive supervision has begun to study how observing or witnessing abusive leadership in the workplace affects third parties. Drawing on social comparison theory and appraisal theories of emotions, my dissertation aims to investigate when and why third parties demonstrate distinct emotional and behavioral reactions toward abusive supervision by arguing that observers’ different responses depend on their past abused experience. Specifically, I propose that third parties experience schadenfreude when past abused experience carried out by the same leader is low. In contrast, third parties experience anxiety when past abused experience is high. Schadenfreude and anxiety negatively associate with subsequent task performance and positively relate to subsequent counterproductive work behavior (CWB), cyberloafing, and employee silence. I used two three-wave field studies to test the theoretical model. In addition, I conducted a set of post hoc analyses to further explore the impact of observing abusive supervision and employees’ own abused experience on fear. By exploring a condition eliciting third parties’ emotions and their behavioral responses, this study attempts to broaden our knowledge on understanding observers’ downward social comparison process in the presence of abusive supervision, the emotion of schadenfreude and anxiety in the workplace, and the performance and behavioral outcomes of observing abusive supervision.