In the title compound, C17H20N2O4S, the thiazolidine (r.m.s. deviation = 0.022 Å) and phenyl rings (major and minor occupancies) are inclined to one another by 6.3 (3) and 10.5 (3)°, respectively. The molecular conformation is stabilized by an intramolecular C—H...S interaction. In the crystal, molecules are linked by C—H...O hydrogen bonds, which generate R22(18), R22(24) and R21(7) ring motifs. Aromatic π–π stacking interactions are also observed.