In the title mol-ecule, C(12)H(10)Cl(2), the torsion angles C(r)-C(r)-C(m)-Cl around the C(m)-C(r) bonds have values of -104.1 (4) and -101.9 (4)°, where C(m) is a methylene and C(r) is a ring C atom. The mol-ecules related by translation along the b axis are arranged into stacks by π-π inter-actions between unsubstituted and substituted aromatic rings of the naphthalene ring system (centroid-centroid distance = 3.940 Å).