Whereas international organizations show a wide variety in their functions, this does not prevent classifying them according to a common framework for analysing their internal power distribution. In this view, the vertical and horizontal models observed in states by constitutional theory have some merit. Since there are differences between states’ and international organizations’ powers, these two models are adapted to the latter by using the concept of function, which pertains to power within states and organizations alike. Combining these two models and their variations results in identifying nine potential regimes of organizations’ power distribution; among these, four are identified as being reflected in actual organizations’ power structures. It is concluded that building a framework for analysing power distribution within international organizations seems possible despite the variety in their functions, and that for this purpose state constitutional theory provides a valuable basis.