Abstract <p>Gadolinium aluminate and barium-doped gadolinium aluminate were prepared by a cost-effective planetary ball milling technique, followed by calcination at 1300°C for 4 h. The doping of Ba into GdAlO₃ led to unique structural and surface properties of the samples. The structural, optical, and morphological characteristics of the synthesized materials were analyzed by powder X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), UV-vis spectroscopy, field emission scanning electron microscope (FE-SEM), and X-ray photoelectron spectroscopy (XPS). The structural phase of the calcinated materials was orthorhombic of the space group <i>Pnma</i>, confirmed by XRD analysis. Rietveld refinement method was used to identify the lattice parameters and R-factors. FTIR spectra showed the metal–oxygen bonds at 654 and 488 cm^–1. The optical band gap energy of the materials was calculated in the range from 3.47 to 3.63 eV, using the Tauc plots from UV-vis analysis. The surface morphology and elemental composition of the materials were analyzed using FE-SEM and energy-dispersive X-ray spectroscopy (EDS). The oxidation states of Gd³⁺, Ba²⁺, and Al³⁺ for the prepared materials were evaluated by XPS analysis. Ba-doped GdAlO₃ samples exhibited dose-dependent antioxidant activity, achieving highest scavenging potential of 34.1%. The enhanced activity was attributed to barium-induced structural modifications, including increased surface reactivity and oxygen vacancy formation.</p>