  In unified gauge theories there exist renormalization group invariant
relations among gauge and Yukawa couplings that are compatible with
perturbative renormalizability, which could be considered as a Gauge-Yukawa
Unification. Such relations are even necessary to ensure all-loop finiteness in
Finite Unified Theories, which have vanishing $\beta$-functions beyond the
unification point. We elucidate this alternative way of unification, and then
present its phenomenological consequences in $SU(5)$-based models.
