The purpose of this study was to investigate the role of group ethical conducting group learning behavior by mediating peer justice. The research method was descriptive-correlation. The statistical population of this study consists of N = 90 employees of the administrative and administrative staff of the Isfahan Municipality. Using Morgan sample size table, n = 73, which were selected by random sampling method. From the peer justice questionnaire, group learning behavior questionnaireand group ethical behavior questionnaire were used. The validity of the questionnaires was confirmed by confirmatory factor analysis and the reliability was confirmed by Cronbach's alpha where all Cronbach's alpha values ​​were higher than 0.7. Data were analyzed using Spss24 and Smart PLS2 software. Pearson correlation test and structural equation modeling were used to test the hypotheses.The results showed that group moral conduct has an effect on peer justice and also peer justice has an effect on group learning behavior. Another result of this study was the mediating role of peer justice in the relationship between group ethical behavior and group learning behavior. In this regard, managers can increase the amount of learning in their individual dimension by developing employees' learning in the group dimension. Therefore, they are suggested to adopt group methods in training and learning of employees in in-service courses.