In the title compound, C21H19NO5S2, the dihedral angles between the formyl-phenyl ring and the two methyl-phenyl rings are 29.3 (3) and 28.9 (3)°, respectively; the dihedral angle between the methyl-phenyl rings is 48.4 (2)°. The C-N-S-C torsion angles are -74.1 (2) and -105.4 (2)°. In the crystal, molecules are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers.