Niobium oxide, sometimes called columbium oxide,^{[citation needed]} may refer to:

• Niobium monoxide (niobium(II) oxide), NbO
• Niobium dioxide (niobium(IV) oxide), NbO₂
• Niobium pentoxide (niobium(V) oxide), Nb₂O₅

In addition to the above, other distinct oxides exist

• general formula Nb_3n+1O_8n−2 where n ranges from 5 - 8 inclusive, e.g. Nb₈O₁₉ (Nb₁₆O₃₈).^[1]
• Nb₁₂O₂₉ and Nb₄₇O₁₁₆

Natural niobium oxide is sometimes known as niobia.