Anniversary of the wedding of Elizabeth II in the UK Date in the current year: November 20, 2018

On November 20, 1947 Princess Elizabeth (future Queen Elizabeth II) married Philip Mountbatten, Duke of Edinburgh at Westminster Abbey in London. Upon their marriage, she took her husband's title and became Princess Elizabeth, Duchess of Edinburgh. In 1952, Elizabeth ascended to the throne. Her wedding anniversary became a flag day as the wedding anniversary of the Monarch.

The choice of flag days in the United Kingdom is managed by the Department for Culture, Media and Sport (DCMS). Along with the Monarch's wedding anniversary, flag days include the Queen's official birthday, Accession Day, Coronation Day, Commonwealth Day, birthdays of members of the Royal Family, Europe Day, and Remembrance Sunday. The flag is also flown on the days of the State Opening and prorogation of the UK Parliament.

On flag days, the Union Flag should be flown from government buildings, i.e. the buildings used by the Crown, civil servants, or the armed forces.