 This article reports on a one-pot sonochemical approach regarding the synthesis of Mn3O4–SnO2 hybrid nanocomposites. Various analytical techniques were utilized to characterize the crystallinity and morphology of the prepared nanocomposites. The functional properties of Mn3O4–SnO2 hybrid nanocomposite were evaluated using electrochemical techniques (Cyclic Voltammetry (CV), Galvanostatic charge–discharge and electrochemical impedance studies (EIS)). A supercapacitor electrode was constructed using the sonochemically synthesized Mn3O4–SnO2 hybrid nanocomposite which showed a specific capacitance (355 F g−1) at a current density (0.5 mA cm−2), and potential range (− 0.1 to + 0.9 V) in 1 M Na2SO4. About 91% specific capacitance was retained after 2000 cycles indicating its high electrochemical stability and capacitance retention.