Research findings often fail to find their way into policy and practice, which is assumed to limit the effectiveness of public health policies and programmes. We evaluated to what extent the Academic Collaborative Centre Limburg (ACCL), a Dutch boundary organization linking policy, research and practice, has improved knowledge transfer and exchange between the three domains. We used a mixed-methods approach. First, stakeholders jointly defined the ACCL's programme theory, showing how the ACCL was supposed to achieve its intended effects. Second, we assessed the achievements of the ACCL in terms of knowledge transfer and exchange on the basis of the programme theory. The ACCL was found to provide a platform for interaction between actors from the policy, research and practice domains, facilitated by integrated network structures. The number of collaborative projects and actors involved in the ACCL increased, but actual cross-domain interaction patterns did not really change. Cross-domain knowledge transfer and exchange still require major boundary-spanning efforts by the ACCL programme leader. Boundary organizations do not automatically produce cross-domain interactions. In addition to infrastructural arrangements, cross-domain knowledge transfer and exchange could benefit from additional cultural changes, like adopting a deliberative approach to policy making and applying constructivist research designs.