This study examined the effects of perceived organizational support and perceived supervisor support on organizational citizenship behavior (OCB), and investigated the moderating effect of organizational vision establishment in these relationships. The study focused on altruism and courtesy among the OCB components proposed by Organ (1988). Research hypotheses were divided into main effect hypotheses and moderating effect hypotheses. For the main effect hypotheses, perceived organizational support and perceived supervisor support were expected to have positive effects on OCB, and organizational vision establishment was also expected to have a positive effect on OCB. For the moderating effect hypotheses, organizational vision establishment was expected to serve as a moderating variable in the relationships between perceived organizational support and supervisor support and OCB. A survey was administered to 25 companies, and 291 valid responses, excluding incomplete ones, were used for analysis. The empirical analysis results are as follows. First, regarding the main effect hypotheses, perceived organizational support had a positive effect on OCB. In contrast, perceived supervisor support did not show a significant effect on OCB. Organizational vision establishment had a positive effect on OCB. Second, regarding the moderating effect hypotheses, organizational vision establishment moderated the effect of perceived organizational support on OCB; specifically, when the level of organizational vision establishment was high, higher levels of perceived organizational support led to greater altruistic behavior. However, no moderating effect was found for courtesy. Organizational vision establishment did not perform a moderating role for perceived supervisor support. These findings demonstrate that for organizations to better elicit OCB from their members, it is necessary to ensure that the organizational vision is clear and well-shared among members, through which the effect of perceived organizational support—representing the organization's commitment to its members—can be amplified. This constitutes the significance of this study.