In the title compound, [Mn(C(20)H(14)N(2)O(2))(N(3))(H(2)O)]·0.5H(2)O, the Mn(III) ion is chelated by the N,N',O,O'-tetra-dentate Schiff base ligand and further coordinated by one azide ion and one water mol-ecule in trans positions, resulting in a distorted fac-MnN(3)O(3) octa-hedral arrangement. The O atom of the uncoordinated water mol-ecule lies on a crystallographic twofold axis. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds help to establish the packing.