Objective: One of the organizations that has a significant role in solving environmental problems, social problems and improving the quality of urban life is the municipality. The social responsibility of the municipality is much more important than other organizations. According to previous studies, when an organization solves social problems in an ethical manner, it builds employee trust in the organization. Organizational trust leads to green behaviors of employees in the organization. Therefore, the present study investigates the impact of organizational social responsibility on employees' green behavior through the mediating role of organizational trust.

Method: The statistical population of the study included all employees of Mashhad Municipality, whose number was 6000 people. According to Morgan's table, 384 employees were selected by available non-random sampling as a statistical sample. The data collection tool was a questionnaire. The face validity of the questionnaire was confirmed using the opinion of experts, the construct validity of the questionnaire was confirmed using factor analysis and the reliability of the questionnaire variables was confirmed using Cronbach's alpha coefficient. Data analysis was performed using SPS software and Smart PayLS software and structural equation modeling method.

Results: The results showed that social responsibility has a positive and significant effect on employees' trust and green behavior. Also, employee trust has a positive and significant effect on employee green behavior. In addition, the mediating role of employee trust in the relationship between social responsibility and green employee behavior was acknowledged.

Conclusion: Organizational managers can increase trust among employees and influence the environmental behavior of employees by taking measures related to social responsibility.