The future operational demand for medical support in Western militaries will likely outstrip available resources, necessitating burden-sharing through medical interoperability with allies and partners. However, the current North Atlantic Treaty Organization (NATO) model of interoperability through standardisation, while achieving high levels of commonality and integration along the operational patient care pathway (OPCP), is high-cost and resource-intensive. We have termed this model assured interoperability. Assured interoperability, while applicable to well-established partnerships with high-resource nations, is unlikely to be feasible when working with resource-limited partners or, potentially, when in a sustained conflict with a near-peer adversary. In these circumstances, there will be a requirement to develop a far less resource-intensive model of medical interoperability with lower levels of commonality, assurance and standardisation than assured interoperability, but that provides a ‘good enough’ OPCP for the operational context. We have termed this pragmatic interoperability. By considering these two types of interoperability, the complete continuum of medical interoperability can be mapped with the full spectrum of partners demonstrating increasing levels of interoperability from pragmatic through to assured interoperability, integrateability and interchangeability, reducing the gap between demand and provision of medical support for operations, increasing operational resilience. This is a paper commissioned as a part of the Defence Engagement special issue ofBMJ Military Health.