PurposeIntegrating the social exchange perspective of helping behavior with self-determination theory (SDT), this study seeks to examine the impact of employees' psychological needs on perceived organizational justice and the impact of perceived organizational justice on employees' helping behavior.Design/methodology/approachCross-sectional and cross-organizational data were obtained from 177 full-time employees employed in 12 small- and medium-sized oil and gas service companies. A partial least squares approach using SmartPLS was employed to test the hypotheses.FindingsResults illustrate that the psychological need for competence and need for autonomy are positively related to perceived distributive and procedural justice, respectively. Moreover, perceived distributive and procedural justice are related to helping behavior. Furthermore, perceived distributive justice fully mediates the relationship between the psychological need for competence and helping behavior, whereas perceived procedural justice partially mediates the relationship between the psychological need for autonomy and helping behavior.Originality/valueFrom a theoretical standpoint, this study offers some theoretical explanations for how the basic psychological needs identified by SDT activate employees' perceived organizational justice. Practically, this study offers several managerial recommendations that help managers manage helping behavior in the organization effectively.