Aluminum oxide nanoparticles/activated carbon (Al2O3NPs/AC) nanocomposite were synthesized using an optimized sol–gel synthesis method. Various characterization techniques, including x‐ray, field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FTIR), UV–visible spectroscopy and cyclic voltammetry, were employed electrochemical properties of the prepared samples. X‐ray diffraction (XRD) analysis revealed higher crystal plane intensities in Al2O3NPs compared to Al2O3/AC nanocomposites. The average crystallite size was determined to be 32 nm for Al2O3 NPs and 20 nm for Al2O3/AC nanocomposites. FE‐SEM showcased the agglomeration of Al2O3 NPs, while the composite exhibited agglomerated Al2O3 NPs embedded in Al2O3/AC nanocomposites. It was found that the band gaps of Al2O3/AC nanocomposite and Al2O3 NPs were 5.5 and 5.6 eV, respectively. Electrochemical analysis through cyclic voltammetry demonstrated that the specific capacitance of Al2O3/AC nanocomposites was six times higher than Al2O3 NPs. This comprehensive investigation provides valuable insights into the enhanced electrochemical performance of the Al2O3/AC nanocomposites, suggesting its potential application in energy storage devices.