In this study polythiophene/nitrogen-doped reduced graphene oxide (Pth/n-rGO) was synthesized by in situ chemical polymerization. The correct synthesis of Pth/n-rGO nanocomposite was checked and confirmed through different spectral, elemental and morphological analysis. The supercapacitor performance of the Pth/n-rGO was higher than those of pure Pth and n-rGO in a neutral medium containing 1 M sodium sulfate. The highest energy density, specific capacitance, and power density values of 13.1 Wh kg−1, 455 F g−1, and 279 W kg−1 were achieved for the Pth/n-rGO nanocomposite. The Pth/n-rGO electrode also revealed commendable cyclic stability which it maintained 94% of its original specific capacitance and 125% coulombic efficiency during 1500 galvanostatic charge-discharge cycles. The superior charge-storage property of Pth/n-rGO is ascribed to the double-layer/pseudocapacitance charge storage synergistic effect. By considering the results of performance and stability for the Pth/n-rGO nanocomposite in this study, it could be good candidate for development of new supercapacitors electrode material.