The present work investigates the performance of Ga-doped ZnO (GZO) and Ca-doped ZnO (CZ) nanopowders as an efficient nanomaterials for the removal of lead ions from aqueous solutions. The sol–gel method was used to synthesise the nanoparticles from zinc acetate dihydrate. To incorporate Ca and Ga in ZnO, adequate quantities of calcium chloride hexahydrate and gallium nitrate hydrate were added to ZnO, and supercritical drying conditions of ethyl alcohol were used. Different Ca and Ga concentrations (1, 2, 3, 4, 5 at.%) were used to synthesise CZ and GZO. The structural and morphological properties of the as-prepared nanoparticles were determined using X-ray diffraction and transmission electron microscopy. Batch-mode experiments were used to remove lead from aqueous solution and to determine the adsorption equilibrium isotherms of lead ions using ZnO doped by 3 at.% of weight of Ca (CZ3) and Ga (GZO3). The effects of temperature, contact time, and pH on the removal of lead ions from aqueous solution by CZ3 and GZO3 were studied.