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 Idaho, as in other jurisdictions, hearsay is typically defined as an out-of-court statement offered to prove the truth of the matter asserted in the statement, and it is generally inadmissible as evidence in court proceedings. This is consistent with the rules found in many evidence codes, designed to ensure the reliability and verifiability of testimony. However, Idaho's rules of evidence, like those of other states and the federal system, recognize numerous exceptions to the hearsay rule. These exceptions may include, among others, statements made under the belief of impending death, statements against interest, certain statements of personal or family history, and records of regularly conducted activity. Additionally, some statements are defined as non-hearsay because they are not offered for the truth of the matter asserted, such as statements offered to show the effect on the listener or to prove the speaker's state of mind. The specific applications and interpretations of hearsay rules and exceptions are governed by the Idaho Rules of Evidence and relevant case law from Idaho courts.