PurposeThe study examined the influence of servant leadership on organisational citizenship behaviour (OCB) of employees in Ghana through the intervening roles of public service motivation (PSM) and the length of time spent with the leader.Design/methodology/approachA structured questionnaire was used to gather data from 328 randomly sampled respondents within the six metropoles in Ghana for data analysis. The partial least squares structural equation modelling (PLS-SEM) was used to address the hypotheses of the study.FindingsThe study found that servant leadership has a significant positive influence on OCB and PSM. The study also found that PSM significantly and positively influences OCB. The study finally established that whiles PSM significantly mediated the relationship between servant leadership and OCB, the length of time spent with leaders did not moderate the servant leadership and OCB nexus.Practical implicationsThe study implies that stakeholders in the local government sector, such as the Local Government Service Board, should emphasise employing or promoting supervisors who are servant leadership-driven to occupy key positions within the local government structure. Efforts could also be made to train the supervisors to acquire servant leadership traits.Originality/valueThe results from the study provide significant insights on how the public sector in Ghana and beyond can identify, develop and maintain servant leaders to promote employees OCB. Also, being a pioneering study in Ghana, the results and recommendations from the study have set the pace for future scholars to discuss issues that engulf the public sector.