Clinical neuropsychology is a sub-field of psychology concerned with the applied science of brain-behaviour relationships. Clinical neuropsychologists use this knowledge in the assessment, diagnosis, treatment, and or rehabilitation of patients across the lifespan with neurological, medical, neurodevelopmental and psychiatric conditions, as well as other cognitive and learning disorders. The branch of neuropsychology associated with children and young people is pediatric neuropsychology.

Clinical neuropsychology is a specialized form of clinical psychology. Strict rules are in place to maintain evidence as a focal point of treatment and research within clinical neuropsychology. The assessment and rehabilitation of neuropsychopathologies is the focus for a clinical neuropsychologist. A clinical neuropsychologist must be able to determine whether a symptom(s) may be caused by an injury to the head through interviewing a patient in order to determine what actions should be taken to best help the patient. Another duty of a clinical neuropsychologist is to find cerebral abnormalities and possible correlations. Evidence based practice in both research and treatment is paramount to appropriate clinical neuropsychological practice.

Assessment is primarily by way of neuropsychological tests, but also includes patient history, qualitative observation and may draw on findings from neuroimaging and other diagnostic medical procedures. Clinical neuropsychology requires an in-depth knowledge of: neuroanatomy, neurobiology, psychopharmacology and neuropathology.