In the title compound, C14H14N2O5S, the molecule exists in the enamine (C=C—NH) tautomeric form. The hydrazone fragment derived from the 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one moiety is approximately planar, with a maximum deviation of 0.1291 (11) Å for the N atom bound to the S atom of the benzensulfonohydrazide group. The latter adopts agaucheconformation relative to the hydrazone N—N bond, with an N—N—S angle of 113.54 (10)°. There is an intramolecular N—H...O=C hydrogen bond that stabilizes the tautomeric form. In the crystal, molecules are linked by N—H...O=C hydrogen bonds into chains extending parallel to [100].