Microfibrillated cellulose (MFC) with reinforcing effects is a useful building block in the fabrication of flexible and thin supercapacitors. Herein, a hybrid tin oxide-cellulose nanocomposite was hydrothermally produced and coated on MFC thin films to form a supercapacitor. The hybrid tin oxide-cellulose thin films were structurally analyzed using scanning electrode microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The cellulose thin film with the highest loading of hybrid tin oxide-cellulose nanocomposite exhibited a specific capacitance of 225.88 F/g at 100 mV/s and 486.38 F/g at 20 mV/s in the three-electrode electrochemical system. In addition, it revealed good cyclic stability up to 40 cycles run continuously with 95% cyclic retention. The high specific capacitance and superior cyclic stability could be related to the enhanced charge mobility and ion diffusion between the solid and electrolyte interface. The cellulose thin film coated with flower-like hybrid nanocomposite showed great potential in energy storage.