Few would question the changing landscape of international higher education, research and innovation (IHERI) or the increased complexities and interconnectedness of the relationships between and among countries of the world. But paradoxically, there is a lack of research on the intersection of these two evolving phenomenon. This article aims to address this by proposing the concept of knowledge diplomacy, instead of soft power, to understand the role of IHERI in building bilateral and multi-lateral relationships based on collaboration, reciprocity and mutuality of benefits. A definition and conceptual framework for knowledge diplomacy are proposed and examined in detail. Three IHERI initiatives -- The Pan African University, the German Jordanian University and RENKEI -- a research network between Japanese and UK universities -- are examined to illustrate how the major elements and principles of the knowledge diplomacy framework can be applied. The article ends by posing questions about the future of knowledge diplomacy and the need for further research.