This paper explores the concept of university-start-up interaction (USUI) as a source of knowledge spillover and innovation. In doing so, we bring together literature on three broad mechanisms that enable knowledge utilization: education, new venture support, and university-industry interaction (UII), as we argue that USUI is a process in which all three are relevant. We first identify USUI practices and how universities and start-ups use these practices to achieve their objectives. Second, we study when the USUI process is mutually beneficial to both actor types in terms of resources. We develop a theoretical framework based on the objectives of the two actor types, the resource-based view, and three generic utilization mechanisms: education, creating new venture support, and UII. Empirically, 36 qualitative interviews were conducted with clean-tech start-ups, universities, and other experts, such as accelerators and incubator facilities in the Boston area, Massachusetts, USA, also known as ''Route 128''. After analyzing the resources exchanged during through 14 practices, we find that USUI is largely based on intangible resources. Second, the resources that universities transfer to start-ups mostly relate to organization and product development, but little to market development. Third, universities can strengthen their (entrepreneurship) education programs and knowledge utilization objectives through USUI, but there is little added value to fundamental research carried out by universities. Overall, we conclude that whether USUI is beneficial largely depends how organizations value their different objectives. Science-based start-ups are more likely to benefit from USUI, whereas start-ups close to market might be better off with other support programs. Universities with a strong focus on fundamental research benefit less from USUI than universities that are more diverse, applied, or have a strong focus on teaching and knowledge utilization. As such, our findings provide insight into the motives of USUI, which enables policy makers and universities to promote knowledge utilization through USUI.