This study investigated the effects of graphite powder on the growth mechanisms of one-dimensional (1-D) single-crystal indium oxide (In2O3) nanostructures. The study was conducted using a chemical vapor deposition (CVD) method at 1000 C-omicron; In2O3 and graphite powder mixed with In2O3, with a weight ratio of 1:1, were used as the source material, while 2 nm-thick n-type silicon (100), coated with a gold catalyst, was used as a substrate. It was observed that nanostructures grew via a Vapor-Liquid-Solid (VLS) growth mechanism when only In2O3 was used, but grew via both VLS and Vapor-Solid (VS) growth mechanisms when graphite powder was used with the In2O3. The morphology and crystal structures of the nanostructures grown were investigated using X-Ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersion X-Ray Spectroscopy (EDS). At room temperature (RT), all the nanostructures showed photoluminescence (PL) spectra at a wavelength of 367 nm in the UV-emission region and at wavelengths of 470 and 630 nm in the visible region.