AbstractBased on the criteria for the improvement of thermal shock resistance mainly two microstructural aspects of thermal stress resistance are discussed: First, the influence of microstructure on thermal shock resistance to fracture initiation, and second, the improvement of thermal shock resistance on the basis of microstructural considerations. In this connection, data of thermal stress resistance (thermal shock and thermal cycling) of various engineering ceramic materials are presented. Using laboratory grades with well‐defined microstructures the interdependence between various microstructural variables and the mechanical and thermal properties, which control the thermal shock resistance, is discussed and the relation to thermal shock resistance is outlined by the example of the two materials, dense and porous reaction‐bonded Si3N4. Moreover, the improvement of thermal shock resistance by microstructural optimization is demonstrated. Some examples of the improvement of thermal stress resistance by developing advanced composite materials are given.The paper is divided into three parts: Part I: Data of Thermal Stress Resistance of High‐Strength Engineering Ceramics Part II: Influence of Microstructure on Thermal Shock Resistance of High‐Strength Engineering Ceramics Part III: Improvement of Thermal Stress Resistance of High‐Strength Engineering