Models of fermion masses

The prospects for understanding the observed pattern of fermion masses and mixing angles are reviewed. We start with a discussion of the experimental determination of the quark mass matrices and the evidence for approximate "texture zeros". A simple (broken) Abelian symmetry capable of generating the texture zeros and ordering the hierarchical structure of the quark masses and mixing angles is described and ideas for the origin of the hierarchy are discussed. The extension of the family symmetry to include leptons is also discussed paying particular regard to the need to obtain large mixing angles in the neutrino sector. Finally we consider the possibility that the structure of fermion masses results from non-Abelian flavour and family symmetries.