AbstractIn this study, banana petiole-based cellulose nanofibril (CNF) films treated with graphene oxide (GO) were prepared and evaluated by means of Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Tensile strengths (TS), dynamic mechanical properties, and thermal stabilities of the films were affected positively when the GO loading was less than 4.4 wt%. From these results, FTIR spectra, and SEM analyses, a strong coupling between the GO and the cellulose matrix could be concluded at lower GO loadings. The TGA and DMA results also suggested that the CNF film treated with 4.4 wt% GO had more char residue, better thermal stability, higher storage modulus, and higher retention ratio when compared to that without treatment. This work provides a new approach for more effective utilization of banana petiole as a feedstock for CNF and GO/CNF composites.