Any witness who is not testifying as an expert witness. Unlike an expert witness, a lay witness does not need to be qualified in any area to testify in court. A lay witness, like any other witness, must limit testimony to matters which they have personal knowledge about. See Federal Rules of Evidence 602. Further, a lay witness may only testify to what is rationally based on their perception or firsthand knowledge, or what is helpful in clarifying testimony for the jury or in determining facts at issue. See Federal Rules of Evidence 701. However, unlike an expert witness, a lay witness may not testify to anything based on scientific, technical, or other specialized knowledge. In federal court and many state courts, such as New York and California, every person is presumed to be a competent to be a witness unless specified otherwise. See Federal Rules of Evidence 601. For example, in California, a witness who is incapable of expressing himself or herself or is incapable of understanding the duty to tell the truth, may be barred from testifying.
[Last updated in June of 2020 by the Wex Definitions Team]