<p>Although unethical pro-leader behavior (UPLB) is conducted to protect leaders, it is considered unethical by the larger society and may be detrimental to the organization. Yet, we have a limited understanding of how and why such behavior emerges in the workplace. Drawing upon normative influence theory and ethics position theory, this study introduces guanxi human resource management practice (guanxi HRM practice) as a novel antecedent for UPLB. We further propose that normative pressure toward guanxi as a mechanism explicates why guanxi HRM practice relates to employee UPLB, and examine the moderating effects of moral relativism and moral idealism on the relationship between normative pressure toward guanxi and UPLB. We received support for our predictions in two scenario-based experiments (Studies 1 and 2) and a time-lagged field study (Study 3). Specifically, we found that guanxi HRM practice was positively related to employees’ normative pressure toward guanxi, leading to UPLB. Moreover, employees with higher (vs. lower) moral relativism or lower (vs. higher) moral idealism, were more likely to engage in UPLB driven by normative pressure toward guanxi. The theoretical and practical implications of these findings are discussed.</p>