The goal of this study was to investigate the structure and optical properties of the prepared PVC/NiO nanocomposites. The samples were characterized via XRD, TEM, SEM, and UV-Vis spectrophotometer experimental measurements. The partial crystal structure of PVC/NiO nanocomposites and cubic structure of NiO nanoparticles were explored by X-ray diffraction. SEM exhibited the good distribution of the nanoparticles in PVC films. Linear optical parameters: refractive index and normalized absorption, increased whenever transmission and reflection reduced by adding NiO nanoparticles. Direct and indirect optical band gaps were obtained from Tauc's formula, and it was found that both direct and indirect optical band gaps decrease as more NiO nanoparticles added. The direct optical band gap decreases from 5.20 to 5.15eV. The optical conductivity increased by increasing the content of NiO nanoparticles. The dispersion parameters: oscillator energy E0, dispersion energy Ed, plasma angular frequency wp, optical momentum of dispersion M-1 and M-3, and static refractive index, were calculated by using Wemple and DiDominco model. The nonlinear optical susceptibility x(3) and nonlinear refractive index n2 were evaluated from the linear optical parameters using semiempirical relation. The increasing in nonlinear parameters x(3) and n2 suggest the use of PVC/NiO nanocomposites for nonlinear opticalapplications.