Canada, the United Kingdom, South Africa, India and Australia make up some of the Commonwealth member countries. Altogether there are 53 member countries from Africa, the Americas, Europe, Asia, the Caribbean and the Pacific, as of 2015.
Other large Commonwealth member countries include Bangladesh, Malaysia, Pakistan, New Zealand and Papua New Guinea.
There are also many small countries in the Commonwealth: the Bahamas, Belize, Malta, Cyprus, Nauru and Tuvalu are some of the smaller Caribbean, European and Pacific members. Thirty-one Commonwealth members are classified as being small states.
All member states in the Commonwealth subscribe to the Commonwealth Charter, which is a document that outlines the Commonwealth's values and principles.
The member countries' leaders meet every two years to discuss issues affecting the Commonwealth. This gathering is called the Commonwealth Heads of Government Meeting. Member countries all have an equal say, regardless of how big, small, rich or poor they are.
The Commonwealth was originally known as the British Commonwealth of Nations and includes self-governing countries from the former British Empire that kept the British monarch as their head of state. Since 1949, membership has been voluntary, and independent countries have been allowed to join. Rwanda and Mozambique are the two most recent members.