Incivility among employees in frontline encounters is prevalent, but little is known about its impact on customers’ ethics-related perceptions and behaviors. Drawing upon the stimulus–organism–response paradigm, this study examines how witnessing incivility among employees can serve as a social atmospheric cue to influence customers’ perceived ethicality of an organization and their subsequent behaviors. According to our results, in response to employee-to-employee incivility witnessed during frontline encounters, customers perceive the uncivil employees’ organization to have a lower level of ethicality. In turn, (...) customers engage more in unethical behavior and less in customer citizenship behavior. We further demonstrate that the negative effect of uncivil employee-to-employee interactions on customers’ perception of the ethicality of an organization is amplified when customers have an a priori perception that the organization is competent. The findings hold theoretical and practical implications for the management of employee-to-employee incivility and unethical customer behavior during frontline encounters. (shrink)