  We investigate ten-dimensional gauge theories whose extra six-dimensional
space is a compact coset space, $S/R$, and gauge group is a direct product of
two Lie groups. We list up candidates of the gauge group and embeddings of $R$
into them. After dimensional reduction of the coset space,we find fermion and
scalar representations of $G_{\mathrm{GUT}} \times U(1)$ with
$G_{\mathrm{GUT}}=SU(5), SO(10)$ and $E_6$ which accomodate all of the standard
model particles. We also discuss possibilities to generate distinct Yukawa
couplings among the generations using representations with a different
dimension for $G_{\mathrm{GUT}}=SO(10)$ and $E_6$ models.
