This study investigates the relationship between extrinsic, intrinsic and social rewards, and the organizational commitment (OC) of 5,522 employees who work for 8 Japanese companies in Vietnam. Hierarchical regression analysis revealed that variables included to measure extrinsic, social and intrinsic rewards were strongly related to OC. Especially, intrinsic rewards had the strongest association with OC. These findings suggest that the antecedents of OC in Vietnam are different from those in the West and China. The comparison between university graduates and others showed that fatigue and autonomy had stronger influence on OC in university graduates than in others. Discussions and implications concerning human resource management in Vietnam are offered.