The molecule of the title compound, C14H15NO4S, is l-shaped, with the central C—S—N—C segment having a torsion angle of −62.9 (2)°. The dihedral angle between the benzene rings is 89.17 (9)°. The C atoms of the methoxy groups are close to coplanar with their attached benzene ring [deviations = 0.084 (4) and −0.192 (5) Å]. An intramolecular C—H...O hydrogen bond occurs. In the crystal, inversion dimers linked by pairs of N—H...O(S) hydrogen bonds generate R22(8) loops.