ABSTRACT: The present experimental studies focuses on the analysis of effect of abrasive particles size on the fracture and values of fracture toughness of vinyl ester composites reinforced with jute fibers and further enhanced by the addition of alumina nanoparticle fillers as a secondary strengthening phase. The laminates of composites of Vinyl Ester with discrepant compositions are prepared by varying alumina nano-filler in the weight proportion of 1% and 2% wt and varied jute fibers in the weight proportion of 10%, 20% and 30% wt. The fracture behavior of vinyl ester polymers was investigated using pre-notched specimens and evaluated based on the linear elastic fracture mechanics parameter,K_c. ASTM D-5045 standard specimen geometries and loading configurations were used; SENB 3-point bending has been investigated. It is supposed from the experimentation that increase in fracture toughness is obtained for composites of Vinyl Ester with increase in addition of alumina filler. The results indicate that the composite comprising 20% jute, 78% vinyl ester, and 2% alumina filler exhibits the highest fracture toughness among all tested compositions. In view of the above an attempt is made in this present investigation conducted to examine the impact of alumina as a filler material in jute–vinyl ester composite. The ability of the composite to resist fracture is increased by the fiber reinforcement. Experimental results indicate that combining vinyl ester with alumina fillers and a jute fiber tailors the composite’s performance effectively, capitalizing on the matrix’s resilience and reinforcing capabilities. The study emphasizes the potential of natural fibre-reinforced composites, augmented with ceramic fillers, as a sustainable option for applications requiring crack resistance, meeting both eco-friendly goals and performance-driven industrial requirements. The experimental results indicate that these composites may be well-suited for applications such as automotive parts, panels, clutches, brake pads, bearings, and sliding components—where crack resistance and lightweight properties are essential.