The shortcomings of existing energy storage devices have prompted an increased interest in exploring supercapacitor devices and novel electrode materials. Integrating rare earth elements (REE) with gallium oxides as the host material might be a promising approach for enhancing supercapacitor performance. This work employs an effective gel matrix route to synthesize rare earth gallium oxides, specifically RE3GaO6 (RE = Eu, Gd, Dy, and Er). The crystallinity, phase purity, optical properties, chemical composition, and morphology of the materials were identified using various characterizations, including XRD, Raman, UV, XPS, and SEM. Electrochemical measures such as CV, GCD, and EIS suggest that the Eu3GaO6-based electrode shows a higher capacitance of 774 F g−1 (552.8 F cm−3) at 1 Ag−1 amidst the synthesized rare earth gallium oxides. Asymmetric supercapacitor electrodes were fabricated using well-performed material and have been studied. The energy and power density of asymmetric supercapacitors are about 33.9 Whkg−1 (13.5 Wh L−1) and 750 W kg−1 (300 W L−1), respectively, with a retention efficiency of 80.8 %.