Prosthetic limb socket is the major part of prosthetic leg and arm. It provides comfortable connection, transfers load, ensures stability between the residual limb and the device. This study aims to investigate tensile, flexural, compression, impact, and water absorption properties of hybrid flax-sisal fiber reinforced epoxy composite. The research also targets to explore its application for prosthetic limb socket. Hand-layup with light compression molding method is utilized to fabricate the composite material from 3 mm fiber length and with fiber-matrix volume % of 40–60, 35–65, and 30–70. Both fibers are treated with 5%NaOH to modify surface properties. Different mechanical tests are conducted to determine composite’s performance on specimens prepared according to ASTM standards. The result shows that the treated composite with flax fiber 25vol%-sisal fiber 15vol%-epoxy vol60% has superior mechanical and physical properties with tensile strength of 68.40 MPa, flexural strength of 145.7 MPa, compression strength of 45.64 MPa, impact energy of 10.83 J, and water absorption percentage of 3.66%. In addition, using ANSYS 2020, prosthetic socket is modeled for the optimum fiber-matrix composition of the composite and it is observed that maximum equivalent von mises stress of 2.214 MPa and deformation of 0.0064 mm. Based on the results and analysis, the selected hybrid flax-sisal-epoxy composite has the potential to be further used as an alternative material for prosthetic socket application.