The title compound, C15H16N2O5S, is a product of the reaction of 2-(2,4-dimeth-oxy-phenyl-amino)-1,3-thia-zol-4(5H)-one with acetic anhydride. The presence of the acetyl and acet-oxy groups in the mol-ecule indicates that the starting thia-zole exists as a tautomer in the reaction mixture with exocyclic amino and enol moieties. The acetyl group is tilted slightly from the heterocyclic ring plane [dihedral angle = 4.46 (11)°], while the acet-oxy group is almost perpendicular to this ring [dihedral angle = 88.14 (12)°]. An intra-molecular acet-yl-meth-oxy C-H⋯O inter-action is noted. In the crystal, mol-ecules are connected into a three-dimensional architecture by C-H⋯O inter-actions.