The objective of this study is to evaluate the performance and emission characteristics of a diesel engine using metallic graphene oxide (GO) and nonmetallic zinc oxide (ZnO) nanoparticles in a Mahua biodiesel blend (B20). At a concentration of 75 mg/L, both GO and ZnO nanoparticles were considered and a surfactant (CTAB) and a dispersant (TWEEN 80) were added at a 1:1 ratio for surface modification. The nanofuel samples were analyzed for stability using a spectrophotometer. The nanoparticles mixed with dispersants and surfactants have shown improved stability. In addition, the injection pressure was varied from 200 to 250 bar. Dispersion of GO and ZnO nanoparticles in BD20 improved performance parameters such as BTE and BSFC. In addition, there was a significant decrease in CO, HC, smoke, and NOx emissions. TWEEN 80-added GO and ZnO nanoparticles in B20 achieved the best results, followed by the CTAB-added nanoparticles. In addition, the operating parameters showed a favorable trend toward improvement at higher injection pressures. At 250 bar, BTE was improved by 4.24% and BSFC was reduced by 3.59% compared to diesel. Also, the CO, UHC, NOx, and smoke opacity were reduced by 47.05%, 15.12%, 18.96%, and 37.09% for B20 + ZnO75 mg/L + TWEEN75 mg/L, respectively.