Hearsay is a statement that (1) the person making it (the declarant) does not make while testifying at the current trial or hearing (in other words, the statement is made out of court); and (2) a party offers as evidence to prove the truth of the matter asserted in the statement.

Hearsay is generally not admissible as evidence—but there are many exceptions to hearsay, and statements that are non-hearsay. The law governing hearsay is usually located in the applicable state or federal rules of evidence, which are interpreted and applied by courts in court opinions or cases.

In Oklahoma, hearsay is typically inadmissible in court under the Oklahoma Evidence Code, which mirrors the Federal Rules of Evidence in many respects. Hearsay is defined as an out-of-court statement offered to prove the truth of the matter asserted and is not made by a witness while testifying at the current trial or hearing. However, there are numerous exceptions to this general rule. For instance, statements that are considered to be against the declarant's interest, certain statements made under the belief of impending death, statements in public records, and statements of personal or family history, among others, may be admissible. Additionally, there are non-hearsay purposes for which a statement may be offered, such as to show the effect on the listener or to impeach the credibility of a witness. The specific applications and exceptions to the hearsay rule are complex and fact-dependent, often requiring the expertise of an attorney to navigate in a legal proceeding.