In the title compound, [Zn(C2H6OS)6]2[Zn(α-P2W18O62)(C2H5OH)(C2H6OS)3(H2O)]·2C2H6OS·C2H5OH·1.5H2O, there are two types of ZnII complex ions. In the [Zn(α-P2W18O62)(C2H5OH)(C2H6OS)3(H2O)]4− anion, the ZnII cation is coordinated by a Wells–Dawson polyanion [α-P2W18O62]6− (POM) via a terminal O atom, three dimethyl sulfoxide (DMSO) ligands, one ethanol ligand and one water ligand in a distorted octahedral geometry. The two independent [Zn(C2H6OS)6]2+ cations exhibit similar distorted octahedral coordination spheres, and both ZnII cations are coordinated by six DMSO ligands. The crystal packing is governed by extensive O—H...O hydrogen bonds and weak C—H...O hydrogen bonds, forming a three-dimensional supramolecular structure. The S atoms of some DMSO molecules are disordered over two positions with different site-occupancy ratios.