The main aim of the study to find out whether organizational commitment has any mediation effect on the relationship between servant leadership and organizational citizenship behavior. Data was collected from 432 managers and staff of private commercial banks in Bangladesh. The respondents were selected using the convenience sampling technique. Structural equation modeling was used for analyzing the collected data. The study reveals that servant leadership has a direct influence on organizational commitment and organizational citizenship behavior, as well as organizational commitment has a direct impact on organizational citizenship behavior. It is also revealed that the relationship between servant leadership and organizational commitment is partially mediated by organizational commitment. The main implication of the study is that employees’ organizational citizenship behavior can be improved by servant leadership of managers through the indirect effect of organizational commitment of employees. The study also pinpoints some limitations as well as future research directions.