Transformative transdisciplinary research settings such as real-word laboratories (RwLs) provide infrastructures for collaboratively testing sustainability solutions in cities. Existing evaluations have focused on learning through experimentation and the tested interventions. Here, we provide an additional focus on the collaboration mechanisms established in real-world experiments. Through the involvement of political-administrative actors, university actors, and civil society actors, real-world experiments can function as initiators for governance networks that drive urban sustainable development, potentially beyond the formal end of real-world experiments. We therefore propose a framework that encompasses governance and transdisciplinary approaches, which can be used to evaluate real-world experiments as new modes of urban governance. The framework was applied to retrospectively evaluate a real-world experiment conducted within a RwL in a German city. We argue that while the framework serves as an evaluative scheme for assessing and comparing real-world experiments, it could also be used to evaluate RwLs as well as transdisciplinary research projects, by emphasizing the governance arrangements formed in those settings. Including this governance perspective expands the debate surrounding the impacts of transdisciplinary sustainability projects.