In this present study, untreated and (5 % NaOH) treated banana and sisal fiber was chosen as the reinforcement along with the various proportionate of polyurethane (PU) loading into vinyl ester (VER) as interpenetrating polymer networks (IPNs) laminate. In this study, banana/sisal (untreated/treated) fiber reinforced IPN laminate was fabricated with the following variant of 0 %, 20 %, 40 % PU loading by using the compressing molding process. Mechanical tests such as tensile, flexural, impact, hardness and water absorption tests were performed and compared in accordance with ASTM standards, to determine their inter-laminar strength of the IPN laminate. In addition, interfacial analysis was also carried out with the help of the scanning electron microscope (SEM) on the broken specimens in order to thoroughly understand the fractured specimen’s micro-structural behavior. Among all tests, the sisal fiber reinforced IPN laminate showed significant surge in all physical tests expects moisture absorption characteristics. © 2021, The Korean Fiber Society for Fibers and Polymers and Springer.