Abstarct: Career plateau is one of the major challenges in human resource management. It limits employees' opportunities for professional growth and career advancement. As a result, it can affect their perceptions of organizational justice, reduce their motivation, weaken their psychological resources, and ultimately decrease their job performance. Although previous studies have confirmed the negative consequences of career plateau, the mechanisms through which it affects job performance have received less attention. In particular, the simultaneous roles of organizational justice and positive psychological capital have rarely been examined. Therefore, this study investigated the effect of career plateau on job performance by focusing on the mediating role of organizational justice and the moderating role of positive psychological capital.This study is applied in terms of its purpose and descxriptive-survey with a correlational approach in terms of its methodology. The statistical population consisted of managers, deputy managers, and experts working at the headquarters of Qarz Al-Hasaneh Mehr Iran Bank. baxsed on Cochran's formula, 170 participants were selected through stratified random sampling. Data were collected using the standardized Career Plateau Questionnaire developed by Milliman (1992), the Organizational Justice Questionnaire developed by Niehoff and Moorman (1993), the Positive Psychological Capital Questionnaire developed by Luthans et al. (2007), and the Job Performance Questionnaire developed by Wright et al. (1995). The data were analyzed using SPSS and SmartPLS software through Partial Least Squares Structural Equation Modeling (PLS-SEM). The results showed that career plateau had a significant negative effect on organizational justice (β = −0.244, t = 3.608). Organizational justice had a significant positive effect on employees' job performance (β = 0.643, t = 12.747). The findings also showed that organizational justice mediated the relationship between career plateau and job performance (β = −0.157, t = 3.450). In addition, positive psychological capital significantly moderated the negative effect of career plateau on organizational justice (β = −0.112, t = 2.591) and the indirect effect of career plateau on job performance through organizational justice (β = −0.072, t = 2.539). The findings indicate that managing the consequences of career plateau requires more than creating opportunities for career advancement. Strengthening organizational justice and developing employees' positive psychological capital can also help maintain and improve job performance.