In this project, I explore the antecedents and consequences of employees’ unethical pro-organisational behaviour (UPB) through the lens of moral decoupling – a moral reasoning process whereby individuals separate their perceptions of morality from their perceptions of performance. First, I argue that employees increase their engagement in UPBs when they (1) see their supervisors doing the same and (2) believe that their supervisors endorse moral decoupling. Second, I argue that employees’ UPBs are only positively related to supervisors’ evaluations of their job performance when supervisors themselves report that they morally decouple. I test these hypotheses in a field sample of supervisor¬–employee dyads and two experimental studies. This combination of studies highlights the complex link between ethics and perceptions of performance in organisations.