Vatican City (2023–present)

The flag of Vatican City is a square 1:1 vertical bicolour of yellow and white bearing the emblem of the Holy See on the white field. The crossed gold and silver keys represent the keys of Saint Peter, while the papal tiara symbolizes papal authority. The design developed from papal merchant and state flags of the 19th century and was formally adopted on 7 June 1929 with the Lateran Treaty. Its proportions and emblem placement were precisely codified again in the Fundamental Law of Vatican City State on 7 June 2023. It is one of only two national flags that are square.