This paper examines the role of training programme accreditation in enhancing interoperability within NATO. A case study of the Slovak JTAC programme supported by SWOT analysis and document review was applied. In this paper we have found that accreditation improves procedural standardisation, technological compatibility and operational performance, while revealing resource and organisational challenges. The study expands understanding of interoperability through a multi-layered framework as a research implication. Recommendations support optimisation of training, resource use and capability development which is a clear practical implication. Originality and value have been achieved by providing a unique empirical view of accreditation as a key tool for strengthening NATO's interoperability.