In the title compound, C22H15NO3S, the plane of the carbazole ring system forms a dihedral angle of 65.06 (4)° with the naphthalene ring system. In the crystal structure, a weak intramolecular C—H⋯O interaction is observed between the naphthalene ring system and the sulfonate group. Two weak intermolecular C—H⋯O interactions are also observed.