Lateral orientated growth of In2O3 nanowire (NW) and nanorod (NR) arrays has been achieved by a vapor transport and condensation method on (001) and (111) surfaces of Si substrates. The single crystalline In2O3 NWs and NRs were grown along [211] in parallel to the Si +/-[110] and lying in the substrate plane. The electrical measurements show that the In2O3 NWs are p-type semiconductor. By N+ doping, the resistivity of the In2O3 NWs has been tuned. The lateral self-aligned In2O3 NW and NR arrays on Si can offer some unique advantages for fabricating parallel nanodevices that can be integrated directly with silicon technology.