传闻证据排除法则，是刑事诉讼法上，判断是否应排除传闻证据的理论，即不采「传闻证据」之法则。应与之区别者，为「传闻法则」。传闻法则是指「规范传闻证据数据使用与否之法则」，其中以排除为原则，使用为例外，因为「法则」当中，一定包含「原则」与「例外」。因此，传闻证据排除法则，其实是「传闻法则」的一部分，也就是传闻法则的「原则」而已。所谓传闻证据，原指「传闻供述证据」，即内容为证人之陈述，供述者仅转述证人之陈述，现泛指「证人之书面传闻」与「证人之证人传闻」。

Hearsay evidence is "an out-of-court statement introduced to prove the truth of the matter asserted therein". In certain courts, hearsay evidence is inadmissible (the "Hearsay Evidence Rule") unless an exception to the Hearsay Rule applies.

For example, to prove Tom was in town, the attorney asks a witness, "What did Susan tell you about Tom being in town?" Since the witness' answer will rely on an out-of-court statement that Susan made, Susan is not available for cross-examination, and it is to prove the truth that Tom was in town, it is hearsay. A justification for the objection is that the person who made the statement is not in court and thus is insulated from cross examination. Note, however, that if the attorney asking the same question is not trying to prove the truth of the assertion about Tom being in town but the fact that Susan said the specific words, it may be acceptable. For example, it would be acceptable to ask a witness what Susan told them about Tom in a defamation case against Susan because now the witness is asked about the opposing party's statement that constitutes a verbal act.