ABSTRACT PbO/PMMA, 3 and 6 mol% ion-doped PbO/PMMA nanocomposites were synthesised using an easy chemical precipitation method. For all of the nanocomposites, the XRD pattern confirms the orthorhombic structure of PbO. The morphology of PbO nanoparticles in PMMA is revealed by the SEM graph. The formation of nanocomposites containing Eu3+ doped PbO nanoparticles in PMMA is confirmed by FTIR. When Eu3+ doped PbO nanoparticles in PMMA are compared to bulk PbO, UV–Vis optical absorption findings demonstrate a blue shift on the absorption band. The optical band gap energy decreases with increasing Eu3+ dopant concentration and is related to red-shifted phenomena. The PL spectra reveal an emission peak associated with blue emission caused by a synthesis defect. For 6 mol% Eu3+ ion doped PbO/PMMA nanocomposites, third-order nonlinear optical parameters such as nonlinear optical susceptibility (χ(3)), nonlinear optical refractive index (n2), and nonlinear optical absorption coefficient (β) are determined by Z-scan technique, and the values are found to be 4.468 × 10−6 esu, 1.257 × 10−7cm2/W, and 9.837 × 10−3 cm/W, respectively. The strong nonlinearity in the current Eu3+ ion-doped PbO/PMMA nanocomposites empowers its promising applications in third-order nonlinear optical devices.