External stakeholder engagement is crucial for delivering value to diverse stakeholders in inter-organizational projects, however, it is not straightforward to organize this in a way that adds value. The intra-organizational focus of previous research offers limited insights into the relevant roles, responsibilities, arrangements and activities in inter-organizational contexts. Moreover, comprehensive empirical studies of the phenomenon are rare. This study explicates how internal stakeholders organize external stakeholder engagement in inter-organizational projects. Our multiple-case study of two infrastructure projects in Northern Europe identified three organizing solutions based on governance, values and dynamism. While governance-based solutions provide an overall structure for organizing external stakeholder engagement, value-based solutions ensure genuine cooperation and dynamism-based solutions facilitate timely organizing. The study develops propositions that constitute a model of how external stakeholder engagement can be organized in inter-organizational projects. The findings have implications for project stakeholder management and mainstream stakeholder research. •External stakeholder engagement is essential in inter-organizational projects.•Organizing external stakeholder engagement in a way that adds value is challenging.•We explored empirically how internal stakeholders organize external stakeholder engagement.•Three organizing solutions were identified based on governance, values and dynamism.•We developed four propositions constituting a model of how external stakeholder engagement is organized.