The wedding of Constantine II, King of the Hellenes, and Princess Anne-Marie of Denmark took place on Friday, 18 September 1964, at the Metropolitan Cathedral of Athens.

Constantine II was the reigning Greek monarch, while Princess Anne-Marie was the youngest daughter of King Frederik IX and Queen Ingrid of Denmark.

The couple, third cousins through both Queen Victoria of the United Kingdom and King Christian IX of Denmark, first met in 1959 at a performance of the Circus Benneweis at Gråsten Palace.

They met again in 1961, and in 1962, Anne-Marie was a bridesmaid at the wedding of Constantine's older sister, Princess Sophia, to Infante Juan Carlos of Spain.

King Frederik IX initially withheld his consent, as Anne-Marie was only 15 at the time, but eventually relented on the conditions that she finish her education and the wedding not be held before her 18th birthday.

[8] As both the bride and groom were descendants of Victoria of the United Kingdom and Christian IX of Denmark, they were closely related to almost all of the royal houses in Europe, many of whom were in attendance.