Commonwealth Day is the annual celebration of the Commonwealth of Nations held on the second Monday in March, and marked by a multi-faith service in Westminster Abbey, normally attended by Queen Elizabeth II as Head of the Commonwealth, with the Commonwealth Secretary-General and Commonwealth High Commissioners in London.

​

The Queen delivers an address to the Commonwealth, broadcast throughout the world.

​

In the year before the quadrennial Commonwealth Games, the Queen starts the Queen's Baton Relay on Commonwealth Day at Buckingham Palace, handing the baton to the first relay runner to start a journey that will end at the Opening Ceremony of the upcoming Games.

​

While it has a certain official status, Commonwealth Day is not a public holiday in most Commonwealth countries, and there is little public awareness of it.