In the present study, a succession of thulium (Tm)-doped zinc oxide (ZnO) nanostructures samples were prepared by sol-gel method using zinc acetate dihydrate, thulium nitrate pentahydrate and sodium hydroxide species with absolute ethanol as solvent. The X-Ray diffraction (XRD) revealed phase purity (hexagonal Würtzite structure) and high crystalline nature of both Tm³⁺ doped and undoped ZnO samples. Furthermore, defects mediated levels in the samples were investigated by means of photoluminescence (PL) spectroscopy. Finally, Tm 4d core level was detected in ZnO: 0.5  mol% Tm³⁺ sample from high resolution X-Ray Photoelectron Spectroscopy (XPS) scan.