The structure of the title salt, C5H6NO+·C9H5O6−, (I), shows that 4-hydroxypyridine has abstracted an H atom from benzene-1,3,5-tricarboxylic acid, yielding a pyridinium cation and carboxylate anion. The two ions form an extensive three-dimensional hydrogen-bonded network throughout the crystal. The hydrogen bonds that comprise the core of the network are considered strong, with O—H...O and N—H...O donor-to-acceptor distances ranging from 2.533 (2) to 2.700 (2) Å. Packing is further enhanced by π-stacking of the cations and anions with like species [centroid–centroid distance = 3.6206 (13) Å].