When designing a wireless communication system, it is essential to have a channel model that can quickly and accurately generate channel impulse response needed for system simulations. Deterministic models such as ray-tracing offer an accurate model of the propagation environment, but their high computational complexity prohibits the intensive link or system-level simulations required during system design. Hence, models with lower computational complexity that could emulate a large class of radio-propagation environments are preferred. These requirements have led to stochastic channel models, which are often classified into geometry-based stochastic models (GSCMs) and nongeometrical stochastic models. In this chapter we focus on the GSCM models.