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 California, hearsay evidence is generally inadmissible in court under the California Evidence Code (Sections 1200-1201). Hearsay is defined as an out-of-court statement offered to prove the truth of the matter asserted in the statement. The rationale behind this rule is to ensure the reliability and credibility of the evidence presented, as hearsay does not allow for cross-examination of the declarant. However, California law recognizes numerous exceptions to the hearsay rule, allowing certain statements to be admitted under specific circumstances. These exceptions can include, but are not limited to, statements made under the belief of impending death, statements against interest, prior inconsistent statements, and certain statements of identification. 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 declarant's state of mind or to explain the listener's subsequent actions. The application of hearsay rules and exceptions can be complex and often requires the expertise of an attorney to navigate in legal proceedings.