This exploratory scoping review was conducted in the context of Belgium’s ongoing military chaplaincy reform, which aims to develop an inclusive and operationally relevant model of spiritual care aligned with NATO interoperability efforts. The objective was to examine international literature to identify transferable concepts, models, and theories. From 348 records, 133 were screened, and 61 peer-reviewed publications (articles and dissertations) were retained. The review revealed a diversity of specific approaches to military spiritual care, but no single dominant model that could be directly applied to the Belgian context. In the absence of universally transferable frameworks, the thematic elements related to chaplains’ roles were abductively organized into four axes that can serve as both conceptual and analytical frameworks: (1) spiritual-existential support across and beyond denominational boundaries; (2) moral guidance and ethical resilience regarding moral injury and value conflict; (3) integration into holistic health and well-being systems; and (4) operational, cultural and command-related contributions. These axes highlight the multidimensional, multi-worldview, and multidisciplinary nature of chaplains’ functions and provide modular building blocks for developing flexible, context-sensitive, and interoperable frameworks. Further research and international collaboration are recommended.