In recent years, there has been a growing focus on Critical Infrastructure (CI) managers due to digital advancements. CI managers oversee essential asset systems crucial for societal functions, and disruptions can have severe consequences. Digitalization offers benefits like improved efficiency and data-sharing. But also presents challenges, including accessing and using data across infrastructures. CI systems are increasingly interconnected, leading to critical interdependencies, requiring effective data-sharing for coordinated planning. This calls for a holistic approach to infrastructure management, adopting a System of Systems (SoS) approach. However, implementing a digital SoS faces difficulties in integrating various IT systems. Inter-organizational IT Governance (IoITG) is crucial for managing IT systems and services across multiple organizations, fostering shared communication, coordination, and control. IoITG aligns IT strategies with organizational goals, enabling a shared vision among CI managers to create a SoS. Establishing IoITG remains unclear, as it requires a new perspective on IT Governance for networked organizations. Existing ITG frameworks haven’t addressed this perspective. Given the nature of CI, IoITG must ensure resilience and proper management of interdependencies without increasing risks. Therefore, the main research question is as follows: How does Inter-Organizational IT-Governance facilitate a System of Systems of critical infrastructures?