Clinical neuropsychologists engage increasingly in forensic consulting activities because such expert opinions are generally relevant, reliable and helpful in resolving certain legal claims, especially those related to traumatic brain injury. Consequently, practitioners of law, medicine and psychology would benefit from understanding the nature of neuropsychological evidence, the standards for its admissibility, and its expanding role in neurolaw. This article reviews important evidentiary rules regulating relevance, preliminary questions, and expert testimony, while tracing federal key court decisions and progeny. Civil and criminal cases are detailed to illustrate the application of these rules and case law to neuropsychological evidence, with suggestions for overcoming motions to exclude such evidence. Expert neuropsychologists have a role in forensic consultation on brain trauma cases, even as the interdisciplinary dialog and understanding among law, medicine, and psychology continues to expand. Copyright © 2013 John Wiley & Sons, Ltd.