Formal and informal partnerships have become key features of education policy and practice in many countries and managing such collaborative arrangements is an important dimension of the role(s) of leaders of educational organizations. Recent research has shown both the tensions and conflict that can develop in partnerships as well as the opportunities and benefits of partnership working for organizations and individuals. This article focuses on the characteristics of partnerships that contribute to their effectiveness, sustainability and success, filling a gap in the literature on educational partnerships. The research data emanate from a qualitative study of partnership working in England. The study used a grounded approach and inductively linked characteristics of partnerships found in the partnership literature with empirical data from a case study of a sub-regional partnership of education and training organizations. This combined evidence is used to conceptualize partnership as a continuum of weak to strong forms of partnership and to develop a table of characteristics which underpin such partnerships. The findings reveal the extent to which trust, networks, norms and values support effective, sustained and successful partnerships. These characteristics are differentiated and may fluctuate during the lifecourse of a partnership but remain fundamental features of partnership working and significantly contribute to the strength and effectiveness of partnerships.