  We present `twin Higgs models', simple realizations of the Higgs as a
pseudo-Goldstone boson that protect the weak scale from radiative corrections
up to scales of order 5 - 10 TeV. In the ultra-violet these theories have a
discrete symmetry which interchanges each Standard Model particle with a
corresponding particle which transforms under a twin or mirror Standard Model
gauge group. In addition, the Higgs sector respects an approximate global SU(4)
symmetry. When this global symmetry is broken, the discrete symmetry tightly
constrains the form of corrections to the pseudo-Goldstone Higgs potential,
allowing natural electroweak symmetry breaking. Precision electroweak
constraints are satisfied by construction. These models demonstrate that,
contrary to the conventional wisdom, stabilizing the weak scale does not
require new light particles charged under the Standard Model gauge groups.
