This study aims to explore the mechanical, thermal, and water absorption properties of the epoxy composites reinforced with Bauhinia purpurea L. fibers (BPF). The composites were produced through compression molding processes with different weight fractions of BPF (5, 10, 15, 20, and 25%). The obtained results highlighted that incorporating 20 wt.% BPF significantly enhanced the composite’s mechanical properties, yielding a tensile, flexural, and impact strength of 55.51 MPa, 71.43 MPa, and 15.86 kJ/m2, respectively. The thermogravimetric analysis (TGA) disclosed that the composites containing 20 wt.% of BPF have a thermal stability up to 391.2 °C. Differential scanning calorimetry (DSC) analysis was performed to examine the heat flow of composites, revealing both endothermic and exothermic reactions with peak values of 19.45 W/g and 19.27 W/g, respectively, for 25 wt.%, BPFs added composites. The composites containing 25 wt.% of BPFs shows higher water absorption rate (16%) and lower contact angle (51°) revealing the hydrophilicity of BPF. The fiber–matrix interface and the associated failure mechanisms were analyzed through scanning electron microscopy (SEM). The findings from the study indicate that the sustainable BPF have the potential to serve as a promising reinforcement material to produce lightweight polymer composites for a various industrial application.