Unethical behavior in the workplace has been widely reported last decades. In view of its serious consequences, there has been a surge of business ethics research focusing on workplace unethical behavior. Especially, an emerging stream of research has begun to systematically theorize and investigate unethical pro-organizational behavior. In the study, we propose a moderated-mediation model to uncover the underlying mechanism and the boundary conditions of the relationship between high performance expectation and unethical pro-organizational behavior. Drawing upon social cognitive theory, we hypothesize that high performance expectation is indirectly related to unethical pro-organizational behavior through moral disengagement. We further propose that perceived industrial competition strengthens the hypothesized relationship and that moral identity weakens the hypothesized relationship. To test those hypotheses, we collected a two-wave field data, one month apart each other, from a group of Chinese retailing employees. In the first wave, 300 employees from 35 retail stores responded to questions assessing their level of high performance expectation, moral identity, moral disengagement, and industrial competition. We also measured a set of control variables at this time. Two hundreds and twenty-five employees completed the second-wave survey which assess their willingness to engage in unethical pro-organizational behavior. To control for nesting effects, we applied multilevel structural equation modeling to analyze the data. Results showed that high performance expectation was positively related to unethical pro-organizational behavior. By applying Monte Carlo simulation, we found that the indirect relationship between high performance expectation and unethical pro-organizational behavior via moral disengagement was significant. We also found a positive interaction between high performance expectation and perceived industrial competition on moral disengagement and a negative interaction between high performance expectation and moral identity on moral disengagement. Finally, we found that: the indirect effect of high performance expectation on unethical pro-organizational behavior via moral disengagement was stronger when employees perceived a high level of industrial competition; the indirect effect of high performance expectation on unethical pro-organizational behavior via moral disengagement was stronger when employees had a low level of moral identity. Our findings are among the first to demonstrate the dark side of leader’s high performance expectation toward subordinates, and explore the psychological mechanism and two key and contrasting boundary conditions. Theoretical and practical implications are discussed.