The microstructure, deformation, and fracture behavior of commercial ABS resins were investigated. Fracture mechanics studies were carried out under both static and dynamic conditions. Fracture toughness was evaluated via the J-integral analysis. In addition static fracture experiments were conducted at different temperatures. The ABS resins assayed here exhibited different deformation and fracture behavior depending on loading mode, matrix molecular weight, strain rate, temperature, rubber content, and morphologies. The reasons for this material’s behavior are discussed with the help of scanning and transmission electron microscopy (SEM and TEM) investigation methods. The major source of toughness seems to be matrix crazing and rubber cavitation under both static and dynamic experiences, but at low strain rates shear yielding also contributes to toughening.