The aim of the present work was to study the effect of fiber surface treatment on the structural, thermal and mechanical properties of luffa fiber and its composites. Fibers were treated with alkali (5% conc.), benzoyl chloride, and potassium permanganate (KMnO₄) (0.05%) at room temperature. The untreated and treated fibers were characterized and morphologically analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The effect of fiber surface modification on the mechanical properties such as tensile strength, flexural strength, ILSS, and impact strength of the composites were investigated. It is observed that chemically treated Luffa cylindrica-reinforced epoxy composites significantly improved the mechanical properties of the composite. The maximum strength properties were found with benzoyl chloride-treated fiber-reinforced composite.