Herein, a detailed analysis of the dielectrical and optical properties of polyvinyl alcohol (PVA)–ZnO nanocomposite films is provided. The ZnO nanoparticles are prepared by the sol–gel process, whereas the nanocomposite films are prepared using the solution casting technique. The dispersion of the ZnO nanoparticles into the PVA matrix is analyzed with X-ray diffraction and a scanning electron microscope. UV–visible spectroscopy is used to investigate the variation in the absorption of the polymer films, as the filler content in the polymer matrix changes. Linear optical parameters, such as the refractive index, extinction coefficient, and optical conductivity, are determined using the absorption and transmission data. The dielectric properties are evaluated with dielectrical and impedance spectroscopy techniques at a frequency range of 100 Hz–5 kHz and a temperature range of 310–360 K. The permittivity of the polymer films is found to increase, as ZnO nanoparticle concentration increases and the temperature rises. Low ZnO loading in the PVA matrix enhances the latter's optical and dielectric properties, which make it useful for optoelectronic applications.