The background of this research is the employee performance plays a very important role in maintaining the growth of the organization. Meanwhile, employee’s performance cannot be separated by the role of organizational citizenship behavior (OCB). On the other hand, leadership style both servant leadership and authentic leadership have a strategic role to empower OCB to increase the employees performance. The objective of this research is to reveal the effect of servant leadership and authentic leadership on employee’s performance through organizational citizenship behavior (OCB) as mediating variable. This research employed a quantitative approach with survey method. The respondents of the research were 58 employees of private bank in Magelang. Moreover, the data were collected by means of questionnaire and the data were analyzed by Partial Least Square (PLS). The results of the research found that servant leadership and authentic leadership have a positive effect on the OCB. Meanwhile, OCB influenced significantly on employees performance. Servant leadership and authentic leadership have a positive effect on the employee’s performance directly and indirectly. Moreover, OCB has mediated the effect of servant leadership and authentic leadership on the employee’s performance.