3,5-Bis(benz­yloxy)benzoic acid

In the title compound, C₂₁H₁₈O₄, the outer benzyl rings are disordered over two resolved positions in a 0.50 ratio. The O—CH₂ groups form dihedral angles of 4.1 (2) and 10.9 (4)° with the central benzene ring, adopting a syn–anti conformation with respect to this ring. In the crystal, the mol­ecules are linked by O—H...O hydrogen bonds and weak C—H...O inter­actions, forming chains along [010].