Purpose: This study aims to investigate the impact of leadership skills (technical, human and conceptual) on organizational citizenship behavior in Vietnamese libraries and the role of organizational culture as the mediator. Design/methodology/approach: A quantitative approach was chosen to gather data from 356 participants working in various libraries in Vietnam. The validity of the measures was assessed through regression analysis and SPSS software. Findings: The results showed that leadership skills do have a significant impact on organizational citizenship behavior, but only human skills had a significant effect on bureaucracy culture. The study also revealed that bureaucracy culture played a significant role in affecting organizational citizenship behavior of organizations. Furthermore, bureaucracy culture was found to mediate the relationship between human skill and organizational citizenship behavior of organizations. Originality/value: This study makes a valuable contribution to the field by exploring the influence of three types of leadership skills on organizational citizenship behavior and the role of leadership in promoting organizational culture. The findings of this research can help organizations understand the importance of leadership skills and organizational culture in promoting good citizenship behavior among employees. The research implications are discussed and can be used to inform decision-making and future research in the field.