Papal inauguration is a liturgical service of the Catholic Church within Mass celebrated in the Roman Rite but with elements of Byzantine Rite for the ecclesiastical investiture of a pope. Since the inauguration of Pope John Paul I, it has not included the 820-year-old (1143–1963) papal coronation ceremony.

It was in the 11th century that the inauguration took the form of a coronation. Along with other ceremonies used at papal inaugurations, a coronation became part of a pope's inauguration ritual from the time of Pope Nicholas II (1059–1061) until 1963. Pope Paul VI, the last pope to be crowned or to use a papal tiara, abandoned the use of his tiara in a ceremony at the end of the second period of the Second Vatican Council.

Over twenty tiaras are held in the Vatican. That of Paul VI is in the crypt of the Basilica of the National Shrine of the Immaculate Conception in Washington, D.C.

A small one is still used to symbolically crown a statue of Saint Peter on his saint's day every year. The first pope for over eight centuries to inaugurate his pontificate without a coronation was Pope John Paul I.