Growth of hillocks has been observed during annealing of sputtered Au films. The height of a hillock is proportional to the area it occupies in the film. This empirical relationship has been used in a model which postulates that hillock growth is associated with stress relief in the Au. The model is able to relate the sign and magnitude of the stress with hillock size and density. The general character of the growth kinetics is also predicted by the model. © 1969 The American Institute of Physics.