This study assesses the relationships among helping intentions and their exogenous antecedents by considering social network ties as mediators. In the model the need for power-prestige, outcome interdependence, and person-organization fit all indirectly influence the helping intentions through the mediation of social network ties comprised of instrumental ties and expressive ties. The model is tested by applying data from employees of different companies, who attend an evening college for advance study. The test results reveal that helping intentions are influenced significantly by expressive ties and instrumental ties, while the influences of outcome interdependence and person-organization fit on expressive ties and instrumental ties are both respectively significant. Finally, the influences of the need for power-prestige on expressive ties and on instrumental ties are insignificant. Implications of the empirical findings are also discussed herein.