It is generally accepted that the power of NGOs has increased with globalization, but to date, few authors have attempted to explain why. Using a model based on institutional economics, this article aims to identify the determinants of this power and wants to open the debate on its legitimacy. One conclusion of the model is that the system of quasi-regulation resulting from the interaction between NGOs and multinational corporations may carry within itself a cultural bias, or that of the people of the most developed countries.