The asymmetric unit of the alpha polymorph of (+)-N-tosyl-L-glutamic acid, C12H15NO6S, contains two independent molecules which differ in conformation. The carboxylic acid groups form an infinite zigzag chain with characteristic R(2)(2)(8) rings running along the b axis. Intermolecular N-H...O and C-H...O contacts mediate the formation of a three-dimensional supramolecular structure described by R(4)(3)(22), R(6)(6)(44) and R(8)(8)(54) graph-set descriptors. Comparison of the extended structure with that of N-(benzenesulfonyl)glutamic acid shows that a subtle difference in the periphery of the molecule, i.e. the replacement of the toluyl group with a phenyl group, can be accompanied by dramatic changes in molecular assembly.