Gadolinium doped Zinc sulphide (Gd3+ZnS) nanoparticles were synthesised by chemical precipitation and studied their structural, surface and optical properties. Predominant peak shifted towards higher angle with dopant concentration corresponds to the structural deformation in the presence of Gd3+ as evident from XRD spectra. Nanoparticles size decreased with the doping concentration. SEM image for different dopant concentration showed large difference in morphology. Chemical compositions were recorded by EDS. HRTEM confirmed the presence of nanocrystalline materials. The results from selected area electron diffraction (SAED) confirmed the XRD results. Band gap energy (Eg) of about 3.92–4.12eV is obtained from Diffused reflectance spectra (DRS) using UV–vis–NIR spectrophotometer. Eg increases with dopant concentration showed strong quantum confinement.