In this work, the structural, optical, and some mechanical properties of PVA/PEO/Fe₂O₃ nanocomposite films prepared by the casting method were investigated, considering the effect of annealing temperature on these properties. FE-Scanning electron microscopy (FE-SEM) images showed improved morphology of the prepared films, resulting in a smooth and uniform surface with annealing. X-ray diffraction analysis revealed that the films were polycrystalline, exhibiting characteristic peaks of PVA and PEO. Increasing the annealing temperature led to higher intensity X-ray diffraction peaks and an increase in crystallite size, indicating that the annealing process improved the crystal structure of the prepared films. The mechanical properties were evaluated using a hardness test, while the modulus of elasticity was calculated using the empirical Mix-Yates equation, the results indicated that the annealing process enhanced the mechanical strength of the PVA/PEO/Fe₂O₃ nanocomposite films. Transmittance and absorption spectra were recorded in the wavelength range of 200–800 nm. The optical properties showed high absorbance in the ultraviolet range and high transmittance in the visible light range. The energy gap was found to be 2.5 eV, decreasing to 2.41 eV after annealing. The optical test results clearly indicate the potential use of the prepared films in optical cut-off filters for UV protection, as well as in tunable broadband optical filters