It is shown that nonrenormalizable gravitational interactions in the Higgs sector of supersymmetric grand unified theories (GUTs) can produce the breaking of the unifying gauge group {ital G} at the GUT scale {ital M}{sub GUT}{approximately}10{sup 16} GeV. Such a breaking offers an attractive alternative to the traditional method where the superheavy GUT scale mass parameters are added {ital ad} {ital hoc} into the theory. The mechanism also offers a natural explanation for the closeness of the GUT breaking scale to the Planck scale. A study of two simple models endowed with this mechanism is presented. {copyright} {ital 1996 The American Physical Society.}