PurposeThe purpose of this study is to look into the relationship between leadership skills, especially technical, human and conceptual skills, and organizational citizenship behavior (OCB), with organizational culture acting as a mediator.Design/methodology/approachFor the purpose of this study, a quantitative strategy was adopted. To collect data, paper/online surveys were administered to 294 individuals in various Vietnamese public organizations. Stata 15.1 was used to assess the reliability, validity and consistency of the measurements. Regression analysis was used to evaluate the proposed hypotheses.FindingsIt was discovered that leadership skills have a significant effect on OCB, which partially supported the hypotheses. However, only conceptual skill was found to have a significant impact on individual OCB (OCBI). Conceptual skill was also found to have a significant impact on supportive culture. In addition, only supportive culture had a significant effect on OCBI. Finally, supportive culture was confirmed to mediate the relationship between conceptual skill and OCBI.Originality/valueThis study adds to the social exchange theory by filling three significant gaps in previous research on leadership skills. First, it investigates the impact of three leadership skills on OCB in public organizations. Second, it examines the role of leadership skills in fostering an organizational culture. Third, the paper concludes by investigating the underlying mechanism through which leadership skills contribute to OCB via the mediation of organizational culture. The implications of these findings for practice are discussed.