Unethical pro-organizational behavior has attracted widespread attention from practitioners and scholars. Although most previous studies have explored its antecedents, less is known about its consequences. The study focuses on analyzing and testing the mechanism and boundary conditions of the influence of employees' unethical pro-organizational behavior on unethical pro-family behavior. To examine our conceptual model, we conducted an experiment study (Study 1) and a two-wave filed study (Study 2) in China. Hierarchical multiple regression and Bootstrap analyses were used to test our hypotheses. The results indicate that employees' unethical pro-organizational behavior is positively related to unethical pro-family behavior, and that employees' work-to-family conflict mediates the relationship between unethical pro-organizational behavior and unethical pro-family behavior. In addition, the relationship between unethical pro-organizational behavior and work-to-family conflict, as well as the indirect influence of unethical pro-organizational behavior on unethical pro-family behavior through work-to-family conflict, are moderated by employees' work-home segmentation preference. These findings suggest the significance of adopting a conservation of resources perspective in comprehending the detrimental effects of unethical pro-organizational behavior. Furthermore, they offer practical insights for managers to formulate specific ethical rules and punishment systems, effectively curbing employees' unethical behavior.