Different actor roles in inter-organizational digital public services are often neither understood nor acknowledged. This can result in challenges regarding the proper design and result in a lack of adoption of these services. In the literature, there exist various taxonomies outlining roles such as users, consumers or co-creators, although their value is limited. We define roles as the expectations regarding the actors and their responsibilities in the governance of a digital public service. The aim of this research is to better understand the various roles in inter-organizational digital service provisioning. This objective is achieved by examining existing classifications and using them to analyze the roles in three inter-organizational cases in Belgium. The multiple-case study reveals natural persons and legal entities often combine several roles. Public administrations have to collaborate to establish inter-organizational digital public services, but might be confronted with different perspectives regarding the end-user or other roles. This might lead to tensions and could have consequences regarding adoption. The results show that intermediary roles performed by non-public sector parties, such as mandate holders or private service providers, are lacking in existing classifications. A novel classification is proposed together with suggestions for the concept of roles, taking a comprehensive view on actor roles in the entire service delivery chain.