La2Se3 nanoflakes were prepared from an aqueous medium by means of a chemical‐bath deposition method and were later utilized as a supercapacitor electrode. X‐ray diffraction (XRD), Fourier transform Raman (FT Raman), field‐emission scanning electron microscopy (FESEM), and contact‐angle measurement techniques were used to study the structural, morphological, and wettability properties of La2Se3 films. The XRD study confirmed the cubic crystal structure of the La2Se3 film. The surface morphology and wettability studies revealed the nanoflake morphology with a hydrophilic surface, which could be beneficial to electrochemical reactions. The electrochemical performance of the La2Se3 nanoflakes was evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The La2Se3 nanoflake electrode exhibited a maximum specific capacitance of 331 F g−1 at a scan rate of 5 mV s−1. An electrochemical impedance study confirmed that the La2Se3 nanoflake electrode has a better supercapacitive behavior in an aqueous electrolyte. The asymmetric supercapacitor device based on the La2Se3 electrode in aqueous electrolyte exhibited good specific capacitance, excellent charge/discharge properties, and superior long‐term cycling stability.