This study investigates dielectric properties of SrTiO3/Ethyl Cellulose (SrTiO3/EC) polymer nanocomposites. SrTiO3 nanoparticles (1–5 wt%) were dispersed in EC using ultrasonication, and the resulting nanocomposites were characterized using XRD, FT-IR, SEM, and impedance spectroscopy. The incorporation of SrTiO3 nanoparticles into the EC polymer matrix significantly improved the dielectric permittivity of the nanocomposites. This enhancement was attributed to the interfacial polarization between SrTiO3 and EC, as well as the increased number of dipoles introduced by the nanoparticles. The dielectric response was found to be dependent on the SrTiO3 loading content, with an optimal loading range identified for maximum dielectric performance. Additional factors influencing the dielectric behavior of SrTiO3/EC nanocomposites included the size and distribution of SrTiO3 nanoparticles, as well as the processing conditions used for nanocomposite preparation. This study aims to optimize the dielectric properties of SrTiO3/EC nanocomposites for potential applications in energy storage devices, capacitors, and other electronic components.