In the title compound, C(18)H(17)Cl(2)NOS, the thio-pyran-one ring adopts a chair conformation, with the substituent in the axial position. The dihedral angle between the two benzene rings is 89.43 (1)°. In the crystal, mol-ecules form inversion dimers through inter-molecular N-H⋯O hydrogen bonds [graph set R(2) (2)(8)].