The amide group in the nine-membered ring of the title compound, C13H17NO5S, has the trans conformation. The molecules are linked into infinite one-dimensional chains by bifurcated intermolecular N-H ... O hydrogen bonds involving the amide O atom and one of the sulfonyl O atoms of the same neighbouring molecule. The compound was prepared by the Friedel-Crafts acylation of 1,2-dimethoxybenzene and glutaric acid anhydride, followed by reduction of the aryl ketone, esterification, chlorosulfonation, treatment with ammonia, saponification and cyclization of the corresponding 5-(2-sulfamoylphenyl)butanoic acid.