Documentary evidence refers to any evidence that is, or can be, introduced at a trial in the form of documents, as distinguished from oral testimony. It is a broad term in evidence law that can include almost any document introduced in trial that is on paper, such as writings, documents, blueprints, drawings, photographs, computer printouts, microfilms, X-rays, files, diagrams, ledgers, books, tapes, audio and video recordings, and papers of any type or description.

Documentary evidence is subject to specific forms of authentication, usually through the testimony of an eyewitness to the execution of the document, or to the testimony of a witness able to identify the handwriting of the purported author. Documentary evidence is also subject to the best evidence rule, which requires that the original document be produced unless there is a good reason not to do so.

In order for documentary evidence to be admitted at trial, it must be relevant and authenticated. Parties are restricted by the original document rule when introducing documentary evidence, but the Federal Rules of Evidence have loosened this requirement through the best evidence rule and allowing for duplicates to be admissible.

In Ireland, documents may be admitted as evidence in court, but there are rules in place to determine their admissibility, and to help the court (or jury) to decide what the documents prove. A document includes anything with writing on it, maps, plans, graphs or drawings, photographs or films, audio recordings, and computer records.

Overall, documentary evidence is an important type of evidence that can be used in court to prove the content of a document. It is subject to specific rules and requirements to ensure its authenticity and relevance.