More and more, international institutions pursue their objectives together in the form of partnerships. Partnerships are established to work towards important policy objectives in relation to global health, environmental protection, and so on. However, the activities of partnerships may lead to questions of responsibility when such objectives are not achieved, or when third party interests are affected. This Forum explores questions of responsibility—the term responsibility being used in a broad sense—that may arise in relation to partnerships and in particular the question of whether responsibility can be shared between the actors that participate in a partnership. These introductory notes provide the necessary background by defining the concepts of partnerships and shared responsibility, and identify ten conclusions on shared responsibility that can be drawn from the case-studies on particular partnerships.