In the title salt, C(6)H(14)NO(+)·C(7)H(6)NO(4)S(-), the 2-sulfamoylbenzoate anion has two intra-molecular hydrogen bonds, forming a five membered C-H⋯O and a seven-membered N-H⋯O twisted ring with ring motifs S(5) and S(7), respectively, while the 2-methyl-4-oxopentan-2-aminium cation also has a stabilizing intra-molecular N-H⋯O hydrogen bond with a twisted S(6) ring motif. The anions form inversion-related dimers with R(2) (2)(8) ring motifs through inter-molecular N-H⋯O hydrogen bonding. The dimers and cations are further linked and stabilized through inter-molecular N-H⋯O and C-H⋯O bonds, forming zigzag-shaped layers that extend along the crystallographic a axis.