Purpose The purpose of this paper is to examine the effect of employees’ perceptions of high-performance work systems (HPWS) on unethical pro-organizational behavior (UPB), and explores the mediating role of psychological ownership and the moderating role of moral identity. Design/methodology/approach The hypotheses were tested by using two-wave survey data that were collected from 306 employees in Chinese enterprises. Findings This study found that HPWS were positively related to UPB, and psychological ownership partially mediated this relationship. Results also revealed that moral identity negatively moderated the relationship between psychological ownership and UPB, and the indirect effect of HPWS on UPB via psychological ownership was weaker for employees high in moral identity. Research limitations/implications The generalizability of the findings is limited, and the cross-sectional data cannot draw any clear causal inference among variables. Practical implications Managers should pay attention to the “dark side” of HPWS and incorporate ethics in the HPWS. Moreover, organizations should provide correct guidance for their pro-organizational behaviors to avoid employees doing bad things for good reasons. Originality/value This study first extends HPWS research to employee’s UPB, uncovers employees’ psychological ownership toward organizations as the pivotal mechanism underlying this relationship, and indicated moral identity can regulate employees unethical behavior.