Abstract <p>Triboelectric nanogenerators (TENGs) have attracted attention as promising technologies for converting mechanical energy into electrical energy. However, conventional planar interfaces suffer from limited contact area and weak adhesion, resulting in low charge transfer efficiency, particularly under wet conditions. In this study, we propose an octopus-inspired adhesive architecture (OIA) based on suction-driven interfacial interactions to enhance triboelectric performance through physical adhesion. The OIA incorporates three-dimensional hollow microcavities inspired by natural octopus suckers, enabling increased effective contact area through structural deformation during contact. Simultaneously, volumetric changes within the cavities generate suction force, improving interfacial adhesion stability. By systematically analyzing preload-dependent deformation and adhesive behavior according to structural diameter, an optimized structure with a diameter of 750&#xa0;μm was identified. The optimized OIA exhibited more than twofold enhancements in both open-circuit voltage and short-circuit current compared with a flat structure under dry conditions, while maintaining stable output performance even in wet environments. Furthermore, the structure-induced hydrophobicity effectively suppressed performance degradation under wet conditions. The generated electrical energy was successfully rectified to stably drive LEDs. This study demonstrates a biomimetic suction-based strategy for enhancing triboelectric interfaces and suggests the potential of structure-engineered adhesive architectures for high-efficiency energy harvesting systems.</p> Graphical abstract <p></p>