In the law, testimony is a form of evidence that is obtained from a witness who makes a solemn statement or declaration of fact. Testimony may be verbal or written, and it is usually made by oath or affirmation under penalty of perjury. Unless a witness is testifying as an expert witness, testimony in the form of opinions or inferences is generally limited to those opinions or inferences that are rationally based on the perceptions of the witness and are helpful to a clear understanding of the witness' testimony.

See also: cross-examination, deponent, depose, deposition, direct examination, hostile witness, leading question, redirect examination, strike from the record