<p>The primary purpose of this study is to select hydrogen peroxide-treated coir geotextiles for the road pavement applications, utilizing the Triangular Fuzzy Analytical Hierarchy Process and Grey Relational Analysis (GRA) methods. 15 different samples of hydrogen peroxide-treated coir geotextiles were prepared by using the Box–Behnken design by varying the concentrations, temperatures, and treatment durations. The triangular fuzzy AHP method was employed to ascertain the weights of different properties by constructing a pairwise matrix based on an absolute number of priority levels for various road pavement characteristics. The various treated geotextiles with hydrogen peroxide were subsequently evaluated to find the optimum rank was done by using Grey Relational Analysis (GRA). The optimum rank was achieved for coir geotextile subjected to treatment at 35&#xa0;°C for three hours with 20% concentration of hydrogen peroxide. The results of the best selected treated geotextile with hydrogen peroxide show a reduction in permeability and water absorption by 9.27% and 11.86%, respectively, 31.40% enhancement in adhesion, 39.09% higher CBR, 35.24% higher interface friction angle, and 13% and 15.01% higher tensile strength in warp and weft direction, respectively, in comparison to untreated geotextile. FTIR and SEM analyses show that the treated coir geotextiles had noticeable changes on their surface, which improved their mechanical and physical properties.</p>