Workplace incivility undermines victims’ well-being, attitudes, and behaviors. Departing from prior research which has largely focused on individual-level drivers and consequences of incivility, this study explores how social factors shape victims’ appraisals and responses to incivility. Drawing on the social appraisal perspective, we examine how a third-party coworker’s emotions and cognitions influence victims’ blame attributions and their constructive (e.g., reconciliation) or destructive (e.g., revenge, avoidance) relational responses toward the instigator. Across two critical incident recall studies with U.S. employees, we investigated the impact of coworker emotions—anger, pity, and sympathy—on victims’ attributions and interpersonal behaviors. Results showed that coworker anger and pity had opposing effects on the victim’s internal and external attributions, while coworker sympathy’s effects on victim attributions depended on the coworker’s blame attributions. The predicted indirect effects of coworker emotions on constructive relational responses were supported (e.g., pity promotes while anger inhibits reconciliation). We also observed some unexpected indirect effects on destructive relational responses (e.g., pity also promotes revenge and avoidance). This research advances theory by shifting focus to the social context, highlighting the interpersonal processes that play a role in how employees appraise and respond to workplace mistreatment.