Glass fiber reinforced polymer (GFRP) rebars offer a high-performing and non-corrosive solution over traditional steel reinforcement in concrete structures, making them ideal for use in harsh environments such as coastal areas, marine structures, and chemical plants. This significantly extends the lifespan of the structures and reduces maintenance costs. Furthermore, the use of GFRP rebars supports sustainable construction practices by reducing the carbon footprint associated with steel production by 43%. These advantages make GFRP rebars a valuable alternative for modern infrastructure projects focused on durability, efficiency, and sustainability. Nevertheless, the behavior of GFRP rebars is significantly influenced by the fiber volume fraction (FVF), which is the ratio of the volume of fibers to the total volume of the composite material. Higher fiber volume fractions generally enhance the tensile strength and stiffness of GFRP rebars, making them more suitable for demanding structural applications. However, increasing FVF can also lead to manufacturing challenges, such as difficulties in ensuring proper resin impregnation and potential void content, which can affect the overall performance and durability of the rebar. The optimal FVF must balance these factors to meet specific performance criteria while maintaining cost-effectiveness and manufacturability. This work presented insights into optimising FVF to achieve desired mechanical properties addressing long-term structural considerations for civil composite applications.