The C=C bond in the title compound, C15H15NO4S, has a Z configuration. The thiazolidine ring is essentially planar [maximum deviation = 0.008 (1) Å for the N atom] and is oriented at a dihedral angle of 59.1 (1)° with respect to the benzene ring. In the crystal, pairs of C—H...O hydrogen bonds link centrosymmetrically related molecules into dimers, generating R22(18) ring motifs. The crystal packing is further stabilized by C—H...π and C—O...π [O...centroid = 3.412 (2) Å and C—O...centroid = 115.0 (1)°] interactions.