Single-crystal GaN nanorings were synthesized by a vapor-solid process. The detailed morphological and crystallographic characterizations of these GaN nanorings were carried out to reveal their formation mechanism. The results presented here demonstrate that the formation of GaN nanorings can be explained by the self-bending of nanobelts due to the surface spontaneous polarization. GaN nanooring is another example of spontaneous polarization-induced nanostructure. (C) 2007 Elsevier B.V. All rights reserved.