State and federal laws and court decisions that address requests for the presence or absence of third party observers during forensic evaluations are reviewed, as are the legal arguments for both their inclusion and exclusion. Potential sources of interference created by observer's presence during the neuropsychological evaluation are outlined with reference to the Ethical Principles of Psychologists and Code of Conduct of the American Psychological Association, the Specialty Guidelines for Forensic Psychologists: Committee on Ethical Guidelines for Forensic Psychologists, and the Standards for Educational and Psychological Testing. The relevant empirical literature dealing with the phenomenon of social facilitation is also presented. Guidelines are offered for use by the neuropsychologist who receives a request for observation by a third party.