The understanding of pedestrian movement in smoke-filled environments is of significant importance in fire safety engineering applications. This chapter presents an overview of the main concepts concerning pedestrian movement in smoke, with a particular emphasis on the adverse effects that it can have on pedestrian evacuation. Several factors are discussed, including fire, pedestrian and environmental factors. Factors associated with the presence of fire relate to the impact of reduced visibility conditions, the presence of asphyxiant/irritant gases and cognitive and emotional influences are also explored. Pedestrian factors include walking speed and pedestrian movement abilities, visual acuity and physical exertion. Environmental factors include geometric complexity, the interaction with way-finding and signage systems, inclination of floor/ground or inclines (similar to stairs), stairs and surface materials. An overview of the current capabilities of pedestrian and evacuation models used in fire safety engineering applications is also presented along with recommendations for future areas of research in the domain of pedestrian movement in smoke.