Abstract We developed a fairness theory perspective to explain the experience of being “singled out” for social undermining from supervisors and coworkers, and tested our predictions across four distinct social contexts. We argued and predicted that attitudinal and behavioral reactions to undermining (from supervisors and coworkers) would be strongest when a correspondingly low level of undermining was found in the social context. The hypothesized cross-level interaction was supported for supervisor and coworker undermining among a sample of officers from the national police force in the Republic of Slovenia (Study 1), replicated for supervisor undermining among soldiers in the US National Guard (Study 2), and further replicated with group-member undermining among a sample of individuals working in student teams (Study 3). We then predicted that justice perceptions would mediate the singled out interaction and tested the mediated-moderation model in a coworker-network context among employees of a restaurant chain (Study 4). The results substantially supported the mediation prediction. These findings from diverse settings demonstrate that considering the social context is important when trying to understand the effects of social undermining behaviors at work.