In the structure of the title compound, C15H13N2O+·C7H7O3S−, the cation has a Z geometry about the ethylene bridge that links the heterocyclic and aromatic rings. The skeleton of the cation is slightly non‐planar; the dihedral angles between the ethylene linkage and the pyridinium ring and p‐hydroxyphenyl ring are 9.2 (1) and 2.0 (1)°, respectively. In the crystal structure, the cations are stacked along the b axis, with a head‐to‐tail orientation, and weak intermolecular C—H⋯N hydrogen bonds link the cations into chains along the a axis. In addition, intermolecular O—H⋯O and C—H⋯O hydrogen bonds between cations and anions link two such chains together with a mean interplanar distance of 3.23 Å between cations.