The fracture behavior of rubber-toughened polymers is governed by two dissipative microscopic deformation and damage mechanisms: matrix shear yielding and crazing. These mechanisms are strongly interconnected with the eventual cavitation of the fine dispersed rubber particles. The present work summarizes and discusses a variety of micromechanical–computational modeling approaches undertaken over the past twenty years aiming at an improved understanding of the relation between microstructure and toughening in this class of materials. The focus is on materials such as ABS where both mechanisms are prevalent