Incorporation of nanoparticles within polymer matrices has proved an enhancement in the dielectric and mechanical behavior of polymers on the laboratory scale. The current study aims to investigate the influence of coupling agent used in functionalization process of titanium dioxide (TiO2) nanoparticles in order to improve the dielectric and mechanical properties of Polyvinyl Chloride (PVC) that mixed with these functionalized nanoparticles. The functionalization of TiO2 nanoparticles was performed using two different silane coupling agents; vinyl silane and amino silane. PVC/TiO2 nanocomposites with different loadings of nanoparticles, up to 3%, were synthesized using solution casting method and with the aid of strong agitation and dispersion tools. The chemical structure of the functionalized TiO2 nanoparticles was characterized by Fourier transformation infrared spectroscopy (FT-IR) and the mechanical