Nanocomposite materials, featuring conducting polymers and aluminum oxide nanoparticles (Al2O3-NPs), are revolutionizing various fields including biomedicine, optoelectronic devices, and dye adsorption. In this study, we report on the synthesis of Al2O3 nanoparticles embedded in a Polyaniline (PANI) matrix for the fabrication of Al2O3/PANI nanocomposite films. The electrodeposition method was employed to deposit these films onto ITO-glass substrates, with concentrations ranging from 5 % to 20 %. The optical properties of the nanocomposites were analyzed using UV–Vis spectroscopy, allowing the determination of the refractive index and absorption coefficients. In addition, the Scherrer equation was used to calculate the average crystallite size, providing insight into the microscopic, ordered regions within the material. With increasing nanoparticle concentration in PANI-Al2O3 nanocomposites, Tauc plots revealed an increase in energy band gaps from 3.70 eV to 3.85 eV. Additionally, optical bandgap energies increased in PANI- Al2O3 nanocomposites, while electrical conductivities decreased with higher Al2O3 NPs content. Incorporation of Al2O3 NPs reduced the degree of conjugated π-bonds in PANI and disrupted the ordered structure of polymer chains. Moreover, the SEM analysis confirmed that the nanocomposite films had a dense, fiber-like structure. Further analysis of FTIR and XRD data revealed interactions between Al2O3 nanoparticles and PANI chains. At lower concentrations, minimal interaction was observed, while higher concentrations resulted in enhanced molecular interactions, leading to improved chain stretching, molecular packing, and larger crystallite sizes. As a result of Al2O3 nanoparticle incorporation, the nanocomposites exhibited conductivity values ranging from 0.12 to 0.02 S cm−1. These engineered nanocomposite films, characterized by high crystallinity, varied electrical conductivities, and controlled band gaps, show promising potential as active components in next-generation optoelectronic devices.