In this research, the effect of organic nanoclay (NC) Closite 20A and graphene oxide (GO) on the compressive, tensile, and three-point bending behavior of polycarbonate (PC) nanocomposites is investigated. The nanocomposite samples are prepared based on injection molding and the masterbatch technique is used for better dispersion of filler in the matrix. The NC masterbatch is made of direct method by the twin-screw extruder device and the GO masterbatch by the solvent method. The results showed that the presence of nanoparticles in the composite improves the elastic modulus, flexural modulus, compressive and tensile yield stress. The best weight fractions between the considered values for PC/NC and PC/GO were 1% and 0.6%, respectively. Higher fractions lead to the formation of agglomerate and degradation of the nanocomposite. Additionally, it was found that the volume change in plastic deformation for thermoplastics was considerable and the assumption of non-dependent potential flow for PC nanocomposites was more appropriate. For simulating the mechanical behavior of PC nanocomposite, the extended Drucker-Prager (EDP) material model was designated and its coefficient were determined by minimizing the difference between the force-displacement curves obtained from three-point bending test and predicted from numerical simulation using the surrogate method. POLYM. COMPOS., 40:3947-3959, 2019.