We report on the rapid production, characterization, and spectral properties of uniform nanorods, nanowires, and nanoplates of rare earth oxides (M2O3, M = Pr, Nd, Sm, Eu, Gd, Tb, Dy). The method developed, based on microwave irradiation (MWI), allows the control of the size and shape of the rare earth oxide nanostructures by varying the MWI reaction time and the relative concentrations of the organic surfactants. The uniformity of the rods and of the wires is demonstrated in their spontaneous assembly into highly ordered 2D supercrystals. The MWI method provides a unique opportunity for the large-scale synthesis of rare earth nanostructures without suffering thermal gradient effects.