Introduction: Servant leadership is one of factors that influence organizational citizenship behavior. On the other hand, spirituality at work develops organizational citizenship behavior which can improve the performance of nurses and the quality of caring services provided by them. This study aimed to determine the direct effect of servant leadership on organizational citizenship behavior as well as the indirect effect of servant leadership on organizational citizenship behavior through mediation effect of spirituality.

Materials & methods: This is a descriptive correlative study based on path analyzing among 152 nurses and 57 head nurses of training hospitals in Rasht. Samples were randomly selected by cluster sampling. Data were collected using servant leadership, organizational citizenship behavior and spirituality at work standard questionnaires and were analyzed using descriptive and inferential statistics and structural equation modeling.

Findings: The results indicated that the status of servant leadership style for head nurses and the status of spirituality at work and organizational citizenship behavior for nurses are relatively desirable. The direct effects of servant leadership on organizational citizenship behavior (t₌1.35, β₌0.08), servant leadership on spirituality at work (t₌2.05, β₌0.18) and spirituality at work on organizational citizenship behavior (t₌10.02, β₌0.75) are all significant. The indirect effect of servant leadership on organizational citizenship behavior through the mediation effect of spirituality at work (t₌6.21, β₌0.6) is statistically significant.

Discussion & conclusions: According to the findings, by servant leadership, nursing managers can enhance the spirituality at work and organizational citizenship behavior among nursing staff improving the quality of care provided for patients.