PurposeThe purpose of the present study was to examine the relationship between empowering leadership and volunteers' service capability in the context of nongovernmental organizations. In doing so, the mediating role of intention to share knowledge was highlighted.Design/methodology/approachData were collected from volunteers from two non-governmental organizations (NGOs) operating in Greece through a web-survey tool. To test our hypotheses, we used bootstrapping analysis.FindingsOur study provides support for the positive effect of empowering leadership (EL) on volunteers' service capability. In addition, we highlighted volunteers' intention to share their knowledge as an underlying mechanism that explains the above relationship.Originality/valueThe present study highlights the important role of EL in increasing service capability in the context of NGOs. Even more, the mediating role of intention to share knowledge provided new knowledge into why EL affects employees' extra-role behavior and more specifically, service capability.