<p>This study examines the mechanical properties and performance improvement of hybrid natural fibre composites reinforced with nettle and glass fibres, modified with pectin biopolymer in a vinyl ester resin matrix. The main goal is to enhance fibre-matrix interfacial adhesion, addressing prevalent issues such moisture sensitivity and insufficient mechanical performance in natural fibre composites. Composites with differing pectin concentrations (5%, 10%, and 15%) were produced via the hand lay-up technique and rigorously assessed through tensile, edge-wise compression, interlaminar shear, impact resistance, hardness and flammability tests. The results indicated that pectin treatment markedly improved mechanical characteristics by enhancing fibre-matrix compatibility. The composite containing 5% pectin (NG1) demonstrated the greatest tensile strength of 114.52 N/mm², in contrast to 111.97 N/mm² for the unmodified composite (NG). The edge-wise compressive strength of the 10% pectin composite (NG2) reached a maximum of 74.67 N/mm², exceeding that of other samples, while the interlaminar shear strength attained a high of 19.15 N/mm² for NG2, compared to 12.36 N/mm² for the control NG composite. Impact resistance consistently increased with higher pectin levels, reaching 5.07 N/mm² for NG3, indicating better toughness. Flammability assessments indicated UL-94&#xa0;V-2 ratings for all composites, with the exception of NG3, which attained a UL-94&#xa0;V-1 classification, signifying enhanced flammability resistance attributed to pectin alteration. The results validate the effectiveness of silane-functionalized pectin in facilitating environmentally sustainable, biodegradable composites with optimal mechanical and fire resistance characteristics. This research offers a promising strategy for the production of economical, durable composites appropriate for automotive, construction, and lightweight structural applications.</p>