Résumé : This paper examines agency costs incurred by microfinance organisations. We argue that differences in agency costs not only stem from differences in ownership form but are also influenced by the amount of power wielded by the chief executive officer (CEO). We proxy for agency costs using operating expenses, asset utilisation, liquidity and tangible asset intensity. Using a sample of 374 microfinance organisations located in 76 countries, we find evidence that agency costs are higher in microfinance organisations set up as non-profits, but only if the CEO is powerful. Our empirical evidence illustrates the importance of installing proper governance mechanisms to minimise agency costs, in particular in the non-profit sector.