  We present a higher order generalized (gravitational) uncertainty principle
(GUP) in the form $[X,P]=i\hbar/(1-\beta P^2)$. This form of GUP is consistent
with various proposals of quantum gravity such as string theory, loop quantum
gravity, doubly special relativity, and predicts both a minimal length
uncertainty and a maximal observable momentum. We show that the presence of the
maximal momentum results in an upper bound on the energy spectrum of the
momentum eigenstates and the harmonic oscillator.
