Shock loading refers to the rapid application of stress over extremely short time scales (nanoseconds to microseconds). The generated shock wave propagates through the material domain, causing an abrupt increase in pressure, temperature, and strain rate, which further leads to non-equilibrium conditions. Under such extreme environments, the atomic lattice undergoes rapid compression followed by release (due to a rarefaction wave), which significantly affects the defect landscape within the material. In this chapter, the authors have covered the fundamentals of shock loading, discussing the discontinuous transition across the shock front and the Rankine–Hugoniot jump condition. The shock wave generation technique and its experimental setup are also provided in the text. Furthermore, a brief discussion on the deformation mechanisms under the shock loading is also included. The influence of various defects (point defects, dislocations, and grain boundaries) on the shock wave propagation and subsequent impact on material properties is pondered over. Moreover, the phase change brought by the shock wave migration is discussed in detail. This chapter could be a great starting point for materials scientists researching in the field of shock loading.