The title Schiff base compound, C14H10ClNO4, has been synthesized by the reaction of 5-amino-2-hydroxybenzoic acid and 5-chloro-2-hydroxybenzaldehyde. The molecule is a zwitterion in the crystal, with the phenolic hydroxy group deprotonated and the imine N atom protonated. It adopts an E configuration about the central C=N double bond. The dihedral angle between the two benzene rings is 3.83 (7)°. Intramolecular N—HO and O—HO hydrogen bonding generates S(6) ring motifs. In the crystal, molecules are connected by intermolecular O—HO and C—HCl hydrogen bonds, forming a supramolecular chain.