The chapter starts with a unified view of glassy states in ferroic materials. Disorder and frustration are the main ingredients responsible for the glassy behaviour, which is identified as a strong frequency dependence of the ac-susceptibility in addition to the occurrence of memory effects detected in zero-field-cooling (ZFC) versus field-cooling (FC) measurements of the temperature dependence of the main ferroic property. Dilute magnetic alloys are taken as prototypical examples of materials displaying glassy behaviour. The physical origin is justified by considering the random distribution of the low concentration of magnetic atoms and their RKKY oscillating exchange interaction. This behaviour is used to inspire lattice models which are (extensions of the Ising model) adequate to study glassy behaviour at a microscopic scale. The particular case of spin glasses is considered in detail and mean-field solutions based on the replica symmetry approach are discussed. Finally, similar models for relaxor ferroelectric and strain glasses are also introduced and briefly described.