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. Commonwealth Day is not a widely marked day in many parts of Canada. Federal government regulations stipulate that the Royal Union Flag, or Union Jack, should be flown alongside the national flag of Canada on or at government buildings and premises, such as federal buildings, military bases, and airports. Get access to all Commonwealth day, Commonwealth day Canada, Commonwealth day theme, commonwealth day is celebrated on 24 may, commonwealth day activities.