  We show that the recently constructed 5-dimensional supersymmetric
$S^1/(Z_2\times Z_2')$ orbifold GUT models allow an appealing explanation of
the observed hierarchical structure of the quark and lepton masses and mixing
angles. Flavor hierarchies arise from the geometrical suppression of some
couplings when fields propagate in different numbers of dimensions, or on
different fixed branes. Restrictions arising from locality in the extra
dimension allow interesting texture zeroes to be easily generated. In addition
the detailed nature of the SU(5)-breaking orbifold projections lead to simple
theories where $b-\tau$ unification is maintained but similar disfavored SU(5)
relations for the lighter generations are naturally avoided. We find that
simple 5d models based on $S^1/(Z_2\times Z_2')$ are strikingly successful in
explaining many features of the masses and mixing angles of the 2nd and 3rd
generation. Successful three generation models of flavor including neutrinos
are constructed by generalizing the $S^1/(Z_2\times Z'_2)$ model to six
dimensions. Large angle neutrino mixing is elegantly accommodated. Novel
features of these models include a simple $m_u=0$ configuration leading to a
solution of the strong CP problem.
