Commonwealth Day is the annual celebration of the Commonwealth of Nations, held on the second Monday in March. While the date holds some official status in select member states of the Commonwealth, observances of the date are not uniform, and the date is not celebrated as a public holiday in most Commonwealth countries.
The event traces its origins to Empire Day, an event initially conceived to celebrate the British Empire. It was originally observed on Queen Victoria's birthday (24 May) or the last weekday before it. In the latter half of the 20th century, the celebration's focus shifted towards emphasising the modern Commonwealth of Nations, and the event was renamed Commonwealth Day in 1958; its date was moved to the second Monday in March in 1977.