Sigillography, also known by its Greek-derived name, sphragistics, is the scholarly discipline that studies the wax, lead, clay, and other seals used to authenticate archival documents. It investigates not only aspects of the artistic design and production of seals, but also considers the legal, administrative and social contexts in which they were used. It has links to diplomatics, heraldry, social history, and the history of art, and is regarded as one of the auxiliary sciences of history. A student of seals is known as a sigillographer.

A seal is a device for making an impression in wax, clay, paper, or some other medium, including an embossment on paper, and is also the impression thus made. The original purpose was to authenticate a document, or to prevent interference with a package or envelope by applying a seal which had to be broken to open the container.