What is a Developmental Disability?

Learn how developmental disabilities are defined by the DD Act.

The Developmental Disabilities Assistance and Bill of Rights Act (DD Act) of 2000 (Public Law 106–402, 106th Congress) defines a developmental disability as a severe chronic disability of an individual that:

  • Is attributable to a mental or physical impairment or combination of mental and physical impairments.
  • Is manifested before the individual attains age 22.
  • Is likely to continue indefinitely.
  • Results in substantial functional limitations in three or more of the following areas of major life activity: self-care; receptive and expressive language; learning; mobility; self-direction; capacity for independent living; economic self-sufficiency.
  • Reflects the individual’s need for a combination and sequence of special, interdisciplinary, or generic services, individualized supports, or other forms of assistance that are of lifelong or extended duration and are individually planned and coordinated.

An individual from birth to age nine, who has a substantial developmental delay or specific congenital or acquired condition, may be considered to have a developmental disability without meeting three or more of the criteria described above if the individual, without services and supports, has a high probability of meeting those criteria later in life.

To learn more about the DD read the following pdfs:


U.S. Capitol

The Developmental Disabilities Assistance and Bill of Rights Act (DD Act) of 2000 (P.L. 106-402) was enacted to improve service systems for individuals with developmental disabilities. Photo: stock.xchng, slonecker.