The papal tiara is a crown that is worn by popes of the Catholic Church from as early as the 8th century to the mid–20th century. It was last used by Pope Paul VI in 1963, and only at the beginning of his reign.

A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself, as distinct from the individual who inhabits it. A specific type of crown is employed in heraldry under strict rules. Indeed, some monarchies never had a physical crown, just a heraldic representation, as in the constitutional kingdom of Belgium.