<![CDATA[General Background: Natural fiber-reinforced polymer composites have attracted significant attention as lightweight, corrosion-resistant, and environmentally friendly materials for structural and industrial applications. Specific Background: Epoxy resin reinforced with woven cotton fabric offers a sustainable composite system, while nanosilica is widely used to modify matrix properties and improve mechanical performance. Knowledge Gap: However, the optimal nanosilica content for balancing tensile strength, compressive behavior, and toughness in cotton/epoxy composites remains unclear. Aims: This study investigated the mechanical properties of woven cotton fabric-reinforced epoxy composites containing 0.5, 1, and 5 wt.% nanosilica. Results: Composite laminates were fabricated by hand lay-up using six cotton layers and tested according to ASTM standards. The tensile results showed that 0.5 wt.% nanosilica provided the highest tensile strength, with a maximum increase of 21.26%. Compressive testing indicated that 1 wt.% nanosilica exhibited superior load-bearing capacity, while toughness analysis showed the highest value for 0.5 wt.% nanosilica at 28,753.17 J/m³. In contrast, 5 wt.% nanosilica resulted in lower performance, likely due to particle agglomeration and non-uniform dispersion. Novelty: This study demonstrates that the optimal nanosilica loading depends on the specific mechanical property evaluated rather than a single universal filler concentration. Implications: The findings support the design of cotton/epoxy nanocomposites for sustainable engineering applications requiring tailored tensile, compressive, and energy absorption properties. Highlights: • 0.5 wt.% nanosilica produced the highest tensile strength and toughness in the composite laminates.• 1 wt.% nanosilica provided the greatest compressive load-bearing capacity.• 5 wt.% nanosilica reduced performance due to agglomeration and non-uniform particle distribution. Keywords: Cotton Epoxy Composite, Nanosilica, Tensile Strength, Compressive Strength, Toughness]]>
