An equestrian seal is a type of seal used in the European Middle Ages, characterized by the depiction of the owner as a mounted warrior in full armour. Originating in the high medieval period, the type was frequently used throughout the 13th to 14th centuries. Continued use into the 15th and 16th centuries was mostly limited to high nobility, especially royalty, while lower nobility switched to the use of simple heraldic seals.

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.