Transformational leadership and project success: The mediating role of team-building

• We undertake a field survey of development projects in the NGO sector.
• Project managers' transformational leadership contributes to project success.
• Team-building partially mediates the effect of transformational leadership on project success.
• Our findings contribute to a better theory of the role of leadership in project success.
• Our findings also form the basis for suggestions how positive effects of transformational leadership can be realized in projects.

Although the effect of transformational leadership on project success is empirically supported, less is known about the mechanisms that explain this effect. To address this issue, we propose the mediating role of team-building as a possible explanation of the relationship between transformational leadership and project success. Based on a field survey of 200 development project managers in the Ethiopian Non-Governmental Organization (NGO) sector, the results of our study indicate that team-building partially mediates the effect of transformational leadership on project success. We discuss the theoretical and practical implications of these findings.