This paper increases scientific knowledge about developmental interventions in inter-organizational processes by applying coordination theory. The interventions interfere intentionally with the process they aim to develop, reveal interdependencies between the participants, and coordinate their interaction for knowledge creation. The three elements of the developmental intervention are: (1) the participants from the different organizations, (2) the boundary objects that represent the inter-organizational business process, (3) the external facilitator, responsible for designing the other two elements, and for establishing among the participants the knowledge-creating conversational interaction mediated by boundary objects. In a successful intervention, the facilitator and the participants co-develop the necessary coordination mechanisms to support the knowledge co-creation of the participants from the different companies towards the common goal, i.e. the shared knowledge about the inter-organizational process.