Abstract: This study examined unique relationships of Person-Organization (PO) fit and Person-Job (PJ) fit with work attitudes and the moderating effects of Person-Supervisor (PS) fit on their relationships. Survey data were obtained from a sample of 199 individuals with different job types and ranks in various companies across several industries including pharmacy, furniture, hospital, electronic equipment, etc., located in Korea. Hierarchical multiple regression analyses were conducted to test three hypotheses. The significance of the incremental variance explained by the addition of the main effect variables or interaction terms were examined in the hierarchical multiple regression analyses. The results show that individuals are able to distinguish between the perceptions of PO_fit and PJ_fit and that both PO_fit and PJ_fit had unique impacts on Organizational Commitment (OC) and Job Satisfaction (JS). The results supported hypothesis 1. However, the results did not support the hypothesis 2 that PO_fit is more likely to relate to OC and PJ_fit is more likely to relate to JS. Regarding hypothesis 3 this study found the effects of PO_fit x PS_fit and PJ_fit x PS_fit on OC. PO_fit or PJ_fit was shown to have stronger relationship with OC when individuals perceive high PS_fit than when individuals perceive low PS_fit. The results indicate that individual’s perceptions of fit with their supervisors can be important moderators strengthening or weakening the relationships between PO_fit or PJ_fit perceptions and OC. The moderating effects of PS_fit were not found in relationships of PO_fit or PJ_fit with JS. The simultaneous examination of three levels of fit perceptions helped provide a more comprehensive picture about the influence of PE_fit perceptions. The implications of the results were further discussed.