Ecological psychology is one of the main alternative theories of perception and action available in the contemporary literature. This Element explores and analyzes its most relevant ideas, concepts, methods, and experimental results. It discusses the historical roots of the ecological approach. The Element then analyzes the works of the two main founders of ecological psychology: James and Eleanor Gibson. It also explores the development of ecological psychology since the 1980s until nowadays. Finally, the Element identifies and evaluates the future of the ecological approach to perception and action. This Element presents an introduction to Ecological Psychology, including its main theoretical roots and its future prospects.