This study aims to determine and analyze the influence of Perception organization support, procedural justice and affective commitment on organizational citizenship behavior, and analyze the effect of mediating affective commitment on the the influence of Perception organization support and procedural justice on organizational citizenship behavior. This research was conducted at Bank BTN Yogyakarta branch office with 51 respondents who were received who had worked at least 2 years. The analytical tool in this study is path analysis. The results of this study indicate that there is a positive and significant influence on organizational citizenship behavior and only affective commitment that does not significantly influence on organizational citizenship behavior. Perception organization support and procedural justice is not significant effect on affective commitment. While affective commitment is not proven to have a mediation between perception organization support and procedural justice on the organizational citizenship behavior.