  In this talk, we discuss an attempt to construct a realistic model of the
grand gauge-Higgs unification. We investigate a 5D SU(6) grand gauge-Higgs
unification model compactified on an orbifold S^1/Z_2. Ordinary quarks and
leptons, together with right-handed neutrinos, are just accommodated into a
minimal set of representations of the gauge group, without introducing any
exotic states in the same representations. The proton decay turns out to be
forbidden at least at the tree level. We also find a correct electroweak
symmetry breaking SU(2)_L \times U(1)_Y \to U(1)_{em} is easily realized by
introducing suitable number of adjoint fermions.
