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Systems of systems (SoS) are interconnected systems that include human, social, organizational, and technological elements. These complex systems have increased in today’s digital society; the elements in a SoS are called constituent systems (CS) and are characterized by managerial and operationally independent interactions to achieve a common goal. Such a goal could be lower cost, robustness, or greater capability. Examples of SoS in modern society include systems in the health, aviation, transport, crisis management, and energy sectors and smart cities. SoS are dynamic and evolve. This dynamic and evolving nature of SoS, coupled with interactions between CS and their managerial and operational independence, poses challenges for risk analysis. Traditional risk analysis methods tend to focus on individual components and known probabilities. This renders them inadequate for the complexities of risk that could arise during CS interactions and can emerge as SoS evolves. The main goal of the thesis is to contribute towards a general process for systematic risk analysis of interconnected societal systems, where modeling methods and tools support each process step. Using a non-traditional approach to safety, the System-Theoretic Accident Model and Processes (STAMP), this thesis validates its suitability for risk analysis in SoS. Results indicated that the approach supported risk analysis in SoS, however, various risk sources with SoS characteristics, such as dynamic structure and latent risks, are not sufficiently handled in STAMP. This thesis demonstrates and proposes a process broadening approach for SoS risk identification, analysis, and modeling adapted for SoS. The Thesis validated this approach by analyzing and modeling risk for a wildfire and COVID-19 management SoS. Further, the thesis contributes to the body of knowledge of a process for identifying risks in SoS. This process demonstrates how broader sources could be identified in SoS and the thesis contributes to knowledge of methods for SoS risk analysis. This systematic identification and analysis of risk in SoS contributes to a conceptual framework for risk analysis in SoS. Furthermore, through a systematic literature review, the thesis contributes to the state of the art in SoS risk analysis, management, and governance providing indications to researchers with areas for research in SoS risk analysis. The thesis enhances the understanding of risk in SoS by bridging the gap between the literature and practice, for risk analysis in non-traditional systems such as SoS. Future work aims to create a general process for systematic risk analysis of interconnected societal systems.