In Developmental psychology, a stage is a distinct phase in an individual's development. Many theories in psychology characterize development in terms of stages.

• Erikson's stages of psychosocial development. Developed by Erik Erikson to describe how individuals relate to their social world.
• Kohlberg's stages of moral development. Developed by Lawrence Kohlberg to describe how individuals reason about morals.
• Piaget's theory. Developed by Jean Piaget to describe how children reason and interact with their surroundings.
• Psychosexual stages. Developed by Sigmund Freud to describe the progression of an individual's unconcious desires.