In this study, the tensile and impact strength of nanocomposites reinforced with graphene nanosheets, basalt, and kenaf fibers were examined by response surface methodology (RSM). RSM with Box-Behnken design (BBD) was adopted as the study design. The polypropylene (PP) was melted and the reinforcements, including graphene nanosheets (at 0, 0.75, and 1.5 wt %), basalt fiber (at 0, 7.5 and 15 wt %), and kenaf fiber (at 0, 7.5, and 15 wt %) were incorporated to the matrix using mixing technique. The length of the fibers was similar for all the samples (5 mm). Tensile and impact tests were run for all samples to determine the weight of each reinforcing filler for gaining the maximum tensile and impact strength. The best tensile strength (34.434 MPa) was attained with a graphene nanosheet of 0.742 wt%, basalt fiber of 15 wt%, and kenaf fiber of 15 wt%. fabrication of composite having optimum levels of each variable yielded products with a 52% higher tensile strength than pristine PP. The best value obtained by impact tests was 129.9 J/m, which was achieved by graphene nanosheet of 0.984 wt%, basalt fiber of 15 wt%, and kenaf fiber of 15 wt%. The best weight combinations of these variables improved the impact strength by 80%. The SEM was also used to monitor the dispersal pattern of each of the reinforcing fillers in the matrix. FTIR characterization was used to analyze the change in the chemical structure of the composite, and results showed that the formation of new bonds between polymer chains and additives enhanced the mechanical strength of the composite