ABSTRACT The incompatible thermoplastic poly lactic acid/carboxylated acrylonitrile butadiene rubber (PLA/XNBR) was prepared, and the effect of graphene oxide (GO) as a reinforcement and glycidyl methacrylate (GMA)-grafted XNBR (XNBR-g-GMA) as a compatibilizer on the properties of PLA/XNBR blend was investigated in this research. The microstructure, mechanical behavior, thermal, rheology, and dynamic mechanical properties of PLA/XNBR composites were investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), tensile test, and dynamic mechanical thermal analysis (DMTA). The incorporation of XNBR-g-GMA improved the compatibility of the PLA/XNBR blend phases, as confirmed by microstructure and DMTA analysis. The results of the mechanical properties showed that with an increase in GO content in the PLA/XNBR/XNBR-g-GMA matrix, there was a significant improvement in tensile strength, Young’s modulus, hardness, and impact strength. In order to validate the experimental mechanical and rheological results, various theoretical models were applied and a good agreement was observed between the theoretical and experimental data.