The title compound, bis(2,4-dinitrophenolato-kappa2O,O')(1,4,7,10,13,16-hexaoxadecane-kappa6O)barium(II), [Ba(C6H3N2O5)2(C12H24O6)], is a 1:1 complex of barium(II)-2,4-dinitrophenolate and 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic beta angle of the P2(1)/n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C-H...O interactions.