This study aimed to identify the influences of compulsory unethical pro-organisational behaviour (CUPB) on employees’ in-role performance and the potential mechanisms between them. Based on the multilevel data from 612 salespeople in China (female = 55.4%; managers = 47.8%; 23–30 years = 55.2%), we found that CUPB was associated with lower employees’ in-role performance. Guilty emotion partially mediated the relationship between CUPB and employees’ in-role performance. Further, we found that the strength between CUPB and guilty emotion was moderated by moral identity. Specially, the regression analysis results showed that the CUPB–moral identity interaction effect significantly predicted feeling guilty. However, the moderated mediation effect of moral identity was not significant. Our results suggest a need for businesses not to force employees too much, to avoid employees engaging in compulsory UPB, and to carefully evaluate both the positive and negative effects of UPB.