The multiplicity of disability definitions can be attributed to the heterogeneity of disability, its multifactoral nature, and its effects across the life span. Of particular concern to the social work profession are those persons with neurocognitive disabilities. Neurocognitive disabilities are ones where a problem with the brain or neural pathways causes a condition (or conditions) that impairs learning or mental/physical functioning or both. Some examples are intellectual disabilities, autism spectrum disorders, and savant syndrome. Neurocognitive disabilities are the most difficult to diagnose often times because of their invisibility. Providing services for people with neurocognitive disabilities is very difficult, and people with these disabilities are among the most vulnerable populations in today's society. This entry discusses neurocognitive disabilities and current and future trends in social work disability practice.