Problem: Public procurement constitutes a large part of the global economy, accounting for 15% of GDP. But it is also responsible for 15% of global greenhouse gas emissions and consumes vast amounts of raw materials as it is strongly focused on linear products. A more circular alternative is the procurement of Product-Service Systems (PSS), which combine products and services. However, research shows that Circular Public Procurements, such as procurements of PSS, are more complex and require deeper procurer-supplier interaction. Yet, the procurer-supplier interaction in the context of public procurement of PSS has not been empirically explored.  Purpose: The purpose of this study is to explore how the interaction between the procurer and supplier throughout the public procurement process can facilitate public procurement of PSS. Method: A qualitative multiple-case study was conducted, exploring four cases of public procurements of PSS between Swedish municipalities and Swedish private companies. Seven semi-structured interviews with interviewees from both sides were conducted. The data was triangulated with case-specific procurement documents.  Results: Procurer-supplier interaction was found to be crucial for procurers and suppliers throughout the public procurement process to make PSS happen and to improve its quality. In both, the preparation and utilisation phase of public procurement, the interaction can bring benefits for procurers as well as for suppliers, thus facilitating PSS.