Given that citizenship challenges the basis and workings of the basic institutions market, state, and civil society, organizational citizenship behaviors (OCBs) become an important moral tenet found in some codes of ethical principles. This study explores service-oriented OCBs and their determinants. Three dimensions of service-oriented OCBs (loyalty, service delivery, and participation) are hypothetically influenced by distributive justice, procedural justice, personal cooperativeness, and the need for social approval through the mediation of organizational commitment. The three dimensions of OCBs are hypothetically influenced by personal cooperativeness, need for social approval, task interdependence, and outcome interdependence through the mediation of social network ties. The model is tested using data from contact employees at several financial holding companies in Taiwan. Test results reveal that the relationships between need for social approval and organizational commitment and those between task interdependence and social network ties are insignificant, whereas all other paths are significant. This study also provides managerial implications and limitations.