Perception is an essentially multisensory process that allows an individual to obtain meaningful information about the surrounding environment. Perception operates in combination with an organism's ongoing actions and, therefore, is an active process by which an individual acquires adaptive behaviors and rich,internal representations.Importantly, at birth, perceptual systems are relatively immature,and individuals are relatively naïve about their world. As development proceeds, perceptual systems mature and help shape an individual's cognitive skills and knowledge. In this entry, we present two essential facets ofperceptual development: first, basic principles that characterize the changes in perceptual abilities early in life; and, second, the current understanding of howfactors both internal and external to the individual (e.g., genesand types of sensory experience) interact during development and how these interactions give rise to new perceptual skills.