The Commonwealth is a voluntary association of 53 independent sovereign states consulting and co-operating in the common interests of their peoples and in the promotion of international understanding and world peace.

Today's Commonwealth is a world away from the handful of British Dominions, which were the first Commonwealth members. From Africa to Asia, from Pacific shores to the Caribbean, the Commonwealth's 1.7 billion people make up 30% of the world's population.

The modern Commonwealth gradually evolved out of United Kingdom's imperial past, mainly through decolonisation, the effects of two world wars and changing patterns of international relations. Today it helps to advance democracy, human rights, sustainable economic and social development within its member countries and beyond. Armed with a common working language and similar systems of law, public administration and education, the Commonwealth has built on its shared history to become a vibrant and growing association of states in tune with the modern world.All of the member states, except for Mozambique, have experienced direct or indirect British rule, or have been linked administratively to another Commonwealth country. At the 1997 summit in Edinburgh, Heads of Government considered the criteria for Commonwealth membership and agreed that in order to become a member of the Commonwealth, an applicant country should, as a rule, have had a constitutional association with an existing Commonwealth member state; that it should comply with Commonwealth values, principles and priorities as set out in the Harare Declaration; and that it should accept Commonwealth norms and conventions.

 
The association has no constitution or charter, but members commit themselves to the statements of beliefs set out by Heads of Government. The basis of these is the Declaration of Commonwealth Principles, agreed at Singapore in 1971, and reaffirmed in the Harare Declaration of 1991. The fundamental political values underpinning the Commonwealth include democracy and good governance, respect for human rights and gender equality, the rule of law, and sustainable economic and social development.

HM Queen Elizabeth II is the Head of the Commonwealth and is recognised as the 'symbol of their free association' by members of the association. Among other things, Her Majesty attends the biennial Commonwealth summits or CHOGMs, and the Commonwealth Games, which are held every four years. At the Edinburgh summit in 1997, for the first time, she addressed the opening ceremony. On every Commonwealth Day a special message from the Queen is broadcast in all member countries.