This study aims to explore the impact of job stress on organizational citizenship behavior (OCB) among university teachers in Bangladesh along with the mediating effect of occupational commitment (OC) on this relationship. An online questionnaire survey using the Google form was conducted to collect data from respondents. 244 valid samples were analyzed using bivariate correlation and regression analyses. The results of hierarchical regression analyses reveal that job stress is negatively and significantly linked to OC when controlling for demographic variables, such as age, gender, educational qualification, type of university, designation, and teaching experience; surprisingly, it has no significant effect on OCB. However, OC is positively related to OCB. Also, the OC has a full mediating influence on the linkage between job stress and OCB. With the support of mediation test, this study suggests OC as a personal resource and mechanism to better manage teacher job stress and improve OCB.