<p>The dielectric properties of zinc oxide (ZnO) doped polypyrrole (PPy) nanocomposites were investigated with emphasis on the effect of thermal polarisation on dielectric constant behaviour. ZnO nanoparticles with an average size of 41.37 nm were synthesised by a precipitation method. The FWHM were obtained from the peaks and the size of the nano particles were calculated by the Debye-Scherrer formula, and the JCPDS data gives the hexagonal nanostructure.PPy was prepared through chemical oxidative polymerisation. ZnO/PPy nanocomposite films were cast by dispersing the constituents in a polyvinyl alcohol matrix. Dielectric measurements were carried out on unpolarized and thermally polarised films at 60&deg;C. The results reveal that thermal polarisation markedly enhances the dielectric constant by improving dipole alignment and reducing structural disorder. An optimal ZnO concentration of 3% and 4% yielded maximum dielectric enhancement, whereas higher loading caused interfacial trapping and reduced dielectric performance.</p>