Controlled-shape synthesis of rare earth doped gadolinium oxide (Gd(2)O(3):Eu(3+) or Tb(3+)) colloidal nanocrystals by non-hydrolytic high temperature (approximately 290 degrees C) solution growth methods is reported. Various shapes of Gd(2)O(3) nanocrystals were synthesized, including spheres, plates, and curved rods. The nanocrystal shape was shown to be dependent on the synthesis parameters, such as type of metal precursor and surfactant, and their concentration ratio. The photoluminescence intensity from rare earth doped Gd(2)O(3) was shown to increase from nanoplates to nanospheres, which is discussed in terms of doping efficiency, crystal structure, and ratio of surface to volume.