Abstract This study underscores the potential of silanized kapok fiber (KF) as a lightweight, eco‐friendly reinforcement for aerospace cabin interiors, emphasizing electrical insulation and mechanical resilience. KF/epoxy composites were fabricated via hand lay‐up, and silane treatment improved flexural, tensile, impact, and storage modulus by 131%, 101%, 145%, and 105%, respectively, due to enhanced fiber‐matrix interaction. Dielectric and impedance spectroscopy revealed reduced dielectric constant, loss, and AC conductivity due to the removal of polar groups and compact composite structure. Additionally, 9% silane concentration decreased water absorption by 3.9% over 400 h due to the tight packing and binding between the fiber and epoxy. These findings demonstrate that silane treatment enhances fiber‐matrix compatibility, improving the mechanical and overall performance of KF/epoxy composites. Highlights KFs are treated with silane coupling agents. Silane treatment enhanced interfacial, chemical and mechanical bonding. Mechanical and electrical properties of composites enhanced with silane grafting on KF. T g of the composites increased after silane treatment. Explored density and demonstrated reduced water absorption properties of the composites.