Interpersonal mistreatment at work often occurs in the presence of others; however, these “others” are rarely examined in empirical research despite their importance to the context of the negative interaction. We conducted 2 experiments to examine how witnessing incivility affects observer reactions toward instigators and targets. In Study 1, participants (N = 60) worked virtually with an ostensible instigator and target. In Study 2, participants (N = 48) worked in vivo with confederates (hired actors) on a job task. Across these 2 studies, we found that observers of incivility tend to punish instigators while their reactions to targets were generally unaffected. Further, the effect of witnessing incivility was mediated by observers’ negative emotional reaction toward the instigator.