In developmental psychology, a stage is a distinct phase in an individual's development. Many theories in psychology characterize development in terms of stages:
- Erik Erikson's stages of psychosocial development expanding on Freud's psychosexual stages, he defined eight stages that describes how individuals relate to their social world.
- Sigmund Freud's Psychosexual stages to describe the progression of an individual's unconscious desires.
- Lawrence Kohlberg's stages of moral development to describe how individuals develop in reasoning about morals.
- Margaret Mahler's psychoanalytic developmental theory contained three phases regarding the child's object relations.
- Jean Piaget's theory of cognitive development to describe how children reason and interact with their surroundings.