<p>Roselle fiber-reinforced epoxy composites are gaining popularity as cost-effective and eco-friendly substitutes for synthetic materials. This study examines how the mechanical, thermal, tribological, and environmental characteristics of epoxy composites reinforced with Roselle fibers are affected by NaOH treatment and alumina fillers at 5%, 10%, and 15%. The composites were created by compression molding, with alumina fillers boosting material performance and NaOH-treated fibers strengthening interfacial bonding. In addition to water absorption, thermal stability, biodegradation, and sliding wear, mechanical characteristics such as tensile, flexural, and impact strength were thoroughly examined. Comp composites containing 10% alumina demonstrated superior performance, which had greater mechanical strength, decreased water absorption, delayed biodegradation, and increased thermal stability. Tribological evaluations showed the lowest specific wear rate (SWR) of 13.28 × 10⁻⁵ mm³/Nm with a coefficient of friction (COF) of 0.278. The ideal parameters were determined by optimization using the Python Simulated Annealing algorithm: alumina content (10.62%), sliding distance (500.33&#xa0;m), and sliding velocity (6.6&#xa0;m/s). This study shows how chemical treatment, alumina fillers, and optimization work together to create high-performance, bio-based composites for environmentally friendly uses. According to the results, these composites are perfect for the packaging, construction, and automotive sectors.</p> Graphical abstract <p></p>