International collaboration is a rapidly growing aspect of university research and a priority of research funding agencies. This article investigates the rationales that underlie Canadian federal research councils' support of international research collaborations. Such support has deep roots in Canadian science and technology policy but has taken on a new importance in the past decade. Even in a context of increasingly costly scientific activity and fierce competition for resources, four sets of goals and associated arguments underpin investments in international collaboration: (1) creating economy of scale, (2) developing human resources, (3) advancing economic and scientific competitiveness and (4) solving global problems. Overall, international research collaborations are today a key policy target in Canada, sought for a variety of reasons but not without challenges.