In order to unveil the mechanism linking fair leadership behavior to employee’ knowledge sharing behavior, a theoretical model, consisting of status competition motivation as a mediator and relative deprivation as a moderator, has been built by integrating social cognition theory and relative deprivation theory. Based on the data collected by the questionnaire survey distributed to 499 employees, our results of moderated mediation analyses indicate that fair leadership behavior positively affects employees’ knowledge sharing behavior through the mediating role of status competition motivation, and the interaction between individual relative deprivation and fair leadership behavior affects employees’ knowledge sharing behavior through the mediating role of dominant position competition motivation. Moreover, our findings can also provide insights on the roles of dominant status competition motivation and prestigious status competition motivation in restraining and promoting knowledge sharing.