The book focuses on the impact response of lightweight sandwich structures. As a kind of lightweight structure, sandwich structure has been widely used in various engineering fields, such as aerospace, ships, vehicles and so on, because of its high specific stiffness, high specific strength and versatility. During service, the sandwich structures may be subjected to various impact loads, which may result in serious damage, thereby reducing the stiffness, strength and load-bearing ca-pacity, thereby shortening the service life and bringing safety hazards. Therefore, an in-depth understanding of impact behavior and failure mechanisms is of great significance for the wider application of sandwich structures. In the past decades, many scholars have conducted in-depth research on related topics. But it is difficult for readers to systematically read all the literature in a short time. This book seeks to succinctly summarize the development and the results achieved in this field. This book focuses on simple, classical structures, such as beams, plates, and shells, under loads such as low-velocity impact, explosive load, and bullet penetrations. The main research methods are theoretical analysis, numerical simulation and experimental investigation. The purpose is to reveal the deep mechanism and lay a foundation for the application of sandwich structure in engineering practice.