(S)quark Masses and Non-Abelian Horizontal Symmetries

We present a model of quark and squark masses which is based on a non-Abelian horizontal symmetry. It leads to order of magnitude relations between quark mass ratios and mixing angles and to the successful exact relation $\sin \theta_C=\sqrt {m_d\over m_s}$ to better than $20\%$ accuracy. The non-Abelian symmetry also ensures the necessary squark degeneracy to suppress FCNC mediated by loops with squarks and gluinos, in the neutral meson systems.