This paper aims to study the influence of organizational justice on OCB at the mediating role of psychological capital. Using a cross-sectional survey design, 200 responses were collected from participants working in the Pakistani banking industry. The data were analyzed by SPSS using hierarchical regression and Pearson r test. The results exhibited that organizational citizenship behavior related positively with organizational justice and also positively related to psychological capital. The study also found that psychological capital fully mediated the OJ– OCB relationship. Similarly, the study also found that the components of psychological capital such as resilience, efficacy, optimism, and hope, partially mediate the OJ–OCB association, thereby increasing the positive effects of organizational justice on OCB optimism. This research helps to understand how to positively influence the OJ–OCB association in the existence of psychological capital. It is concluded that psychological capital can increase positive consequences of organizational justice on OCB.