Problem Statement: Defined as the actions that personnel voluntarily take beyond their formal job description, organizational citizenship behavior is regarded as a premise for shared leadership, a management style that is frequently used in organizations today. The relevant literature suggests that organizational citizenship behavior can provide the team effectiveness required for the successful practice of shared leadership. The procedure of this leadership style involves sharing tasks and responsibilities, and thus requires cooperation. Considering the personnel's expectations for this type of leadership, it is not possible for members who exhibit poor organizational citizenship behaviors to meet these expectations. A school under shared leadership functions as a team, and all members of this team must share leadership in every field and devote themselves to performing their responsibilities if they wish to achieve the school's mission satisfactorily. This study tried to discover the extent to which teachers' levels of commitment to organizational citizenship in primary schools predict the successful practice of shared leadership. Purpose of Study: The author wished to determine the extent to which teachers' organizational citizenship behaviors in primary schools predict the successful practice of shared leadership. Methods: This research is a correlational study. The sample comprised 364 primary school teachers working in Zonguldak. The data were collected using a group-level organizational citizenship behaviors scale and a shared leadership perception scale. Findings and Results: The findings of the study revealed that there is a high level of positive correlation between primary school teachers' levels of organizational citizenship behaviors and the successful practice of shared leadership. For example, the sub-dimension of organizational citizenship behaviors towards individuals of the organization predicts significantly in a positive way and at a high level the joint completion of tasks, mutual skill development, decentralized interaction among personnel, and emotional support dimensions of shared leadership. In addition, the sub-dimension of organizational citizenship behaviors towards the organization predicts significantly at a low level the successful practice of joint completion of tasks and emotional support dimensions of shared leadership, but this sub-dimension offered no significant prediction of the successful practice of mutual skill development and decentralized interaction among personnel. According to the findings, it can be stated that organizational citizenship behaviors are significant predictors of the successful practice of shared leadership. Conclusions and Recommendations: According to the findings of the study, when the correlations between group-level organizational citizenship behaviors and both total shared leadership and its factors are examined, it can be seen that the correlation between the level of individual organizational citizenship behaviors and shared leadership is higher than other correlations. It is also understood that the level of organizational citizenship behaviors predicts positively and highly the successful practice of shared leadership and that the prediction of the sub-dimension of organizational citizenship behaviors towards individuals is more significant and at higher level than that of the organizational citizenship behaviors towards the organization. There is also research in the literature supporting the finding that organizational citizenship behaviors, particularly the individual-oriented ones, predict significantly the successful practice of shared leadership. Therefore, it was confirmed that the level of organizational citizenship behaviors predicts shared leadership significantly to a considerable extent. This situation is also understood from the goodness of fit indices. As a result, it can be suggested that the organizations planning to employ shared leadership in their executive structures should take actions to empower organizational citizenship behaviors as a premise of shared leadership.