The development and outcome of intellectual disability involves an exploration of the etiology of intellectual disability, the development of students with an intellectual disability, and the outcomes or results for an individual with an intellectual disability. In other words, the development and outcome of intellectual disability involves the consideration of the causes of intellectual disability, the developmental perspectives and learning characteristics of students with intellectual disability, and the adult life or post-school outcomes (i.e., employment, postsecondary education, and independent living) experienced by individuals with intellectual disability. This entry explores these key causes, perspectives, and outcomes in detail.