Key features of these institutions are examined through the use of conceptual frameworks and ten in-depth case studies from all regions of the world. Distinguishing characteristics such as shared governance and management practices; collaborative academic programs and the development of joint laboratories, research networks, and centers of excellence are analyzed. A study of the driving rationales for IJUs and RUs reveals commonalities and stark differences. While international joint universities are commonly single campus institutions, regional universities can be single, multiple campus or virtual. IJUs and RUs are understudied phenomena as more attention and research is focused on the rise of international branch campuses. Academic leaders, policy makers, higher education scholars and students will benefit from the analysis of the key features, rationales and benefits of international collaborative university models and how they can contribute to 1) providing increased and diversified access to education, 2) promote regional identity and facilitate bilateral and regional collaboration for education, research and innovation; 3) contribute to stronger regional and international relations between countries through knowledge diplomacy; and 4) address contemporary global and regional  issues. At the same time, it is important to acknowledge potential risks and uncertainties related to quality assurance, qualification recognition, financial stability, research integrity, knowledge security, and sustainability that can be linked to collaborative models of international higher education institutions.