Questioned document examination (QDE) is the forensic science discipline pertaining to documents that are (or may be) in dispute in a court of law. The primary purpose of questioned/forensic document examination is to answer questions about a disputed document using a variety of scientific processes and methods. Many examinations involve a comparison of the questioned document, or components of the document, to a set of known standards. The most common type of examination involves handwriting wherein the examiner tries to address concerns about potential authorship.

A document examiner is often asked to determine if a questioned item originated from the same source as the known item(s), then present their opinion on the matter in court as an expert witness. Other common tasks include determining what has happened to a document, determining when a document was produced, or deciphering information on the document that has been obscured, obliterated or erased.

The discipline is known by many names including forensic document examination, document examination, diplomatics, handwriting examination, or sometimes handwriting analysis, although the latter term is not often used as it may be confused with graphology. Likewise a forensic document examiner is not to be confused with a graphologist, and vice versa.