Psychologists began to give evidence in European courts about a century ago. Their original role, heavily influenced by the development of experimental psychology, which has been retained and is successfully being applied to cases. Psychologists have subsequently developed an important clinical role in judicial proceedings, which complements the role fulfilled by forensic psychiatrists. The author argues that psychologists now function more independently than ever before, the demand for their services is growing rapidly both in civil and criminal proceedings, and their status is greatly enhanced.