Gallium oxide nanowires, nanotapes and nanosheets were synthesized by carbothermal method using carbon nanotubes as reactant and characterized by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was confirmed that gallium oxide nanostructures were single crystalline. Photoluminescence (PL) spectrum of the product displayed an intensive blue light emission peak at 487 nm at room temperature.