The disordered and ordered structures of nonstoichiometric titanium monoxide TixOz ≡ TiOy (y = z/x) containing structural vacancies simultaneously in the nonmetallic and metallic sublattices were studied. In the stoichiometry range from TiO0.9 to TiO1.1, an ordered monoclinic phase [space group C2/m (A12m/1)] of the Ti5O5 type is formed in the TiOy monoxide at temperatures below 1300 K. The disorder–order TiOy–Ti5O5 phase-transition channel involves Lifshitz {k10} and non-Lifshitz {k4} and {k11} star rays. The ordering proceeds as a first-order phase transition with a decrease in the volume of the basal cubic lattice. The titanium and oxygen distribution functions in the metallic and nonmetallic sublattices of titanium monoxide are calculated. The domain of allowed values is determined for the long-range order parameter.