Low interfacial adhesion between polar aramid fibres and non-polar elastomeric matrices remains a major challenge in the development of high-performance rubber–fabric composites. In this study, microwave-assisted CBS functionalisation was employed to enhance the interfacial adhesion between woven Kevlar® fabric and natural rubber (NR) composites. The aramid fabric was initially rubberised using an EPDM masterbatch containing different concentrations of N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and subsequently subjected to controlled microwave irradiation prior to composite fabrication. The adhesion performance of the microwave-functionalised composites was evaluated using the ASTM D413 90° strap peel test, while Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) were employed to investigate the chemical, surface, thermal, and morphological characteristics of the treated aramid fabric. The peel response increased from the untreated control to the treated conditions, remained nearly unchanged between E1 and E2, increased further through E3 and E4, and then decreased at E5. The highest mean maximum peel load was observed for E4, corresponding to an improvement of approximately 38% relative to the untreated control. FTIR and XPS analyses provided complementary evidence of changes in the treated/rubberised fabric surface chemical environment and the presence of sulphur-containing treatment-derived species associated with the retained interfacial treatment layer, whereas TGA revealed that the treatment preserved the inherent thermal stability of the aramid fibres. SEM observations further demonstrated increased surface irregularity of the treated/rubberised fabric and improved rubber retention, indicating enhanced fibre–rubber interfacial interaction. Overall, the present results demonstrate the potential of microwave-assisted CBS treatment for improving the interfacial adhesion of aramid fabric–reinforced natural rubber composites under the investigated laboratory conditions.