The reaction of the N-phenyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide ligand with zinc acetate dihydrate in a 2:1 molar ratio yielded a yellow solid, which was crystallized from DMSO to obtain the title compound, [Zn(C17H16N3S)2]·C2H6OS. The ZnII ion is four-coordinated in a distorted tetrahedral environment by two deprotonated ligands. Each ligand acts as an N,S-donor, forming a five-membered metallacycle. The maximum deviation from the mean plane of the N-N-C-S chelate group is 0.0029 (14) Å for the N-donor atom of one ligand and 0.0044 (14) Å for the non-coordinating N atom of the second. The dihedral angle between the planes of the two chelate groups is 72.80 (07)°. Bond lengths in the ligands are compared with those in the crystal structure of the free ligand. In the crystal, complex molecules are connected by dimethyl sulfoxide solvate molecules via N-H...O hydrogen-bonding interactions, building a one-dimensional hydrogen-bonded polymer along the a-axis direction. The S atom and one C atom of the dimethyl sulfoxide solvate molecules are disordered over two sets of sites with an occupancy ratio of 0.6:0.4.