In the United States, special needs is a term used in clinical diagnostic and functional development to describe individuals who require assistance for disabilities that may be medical, mental, or psychological. For instance, the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases 9th edition both give guidelines for clinical diagnosis. People with Autism, Down syndrome, dyslexia, blindness, or cystic fibrosis, for example, may be considered to have special needs.

In the United Kingdom, Special needs often refers to special needs within an educational context. This is also referred to as special educational needs (SEN).

More narrowly, it is a legal term applying in foster care in the United States, derived from the language in the Adoption and Safe Families Act of 1997. It is a diagnosis used to classify children as needing "more" services than those children without special needs who are in the foster care system. It is a diagnosis based on behavior, childhood and family history, and is usually made by a health care professional.