Non-applicants
Egypt, Myanmar and Iraq have never shown an interest in joining the Commonwealth, although they are eligible to do so, having histories of British rule. Sudan, Somalia, Eritrea, Bahrain, Kuwait, Jordan and Oman similarly are not members. Other countries with historical links to the United Kingdom or other Commonwealth countries that could be potential Commonwealth members, but have shown no indication of a wish to join, include Nepal, Bhutan, Afghanistan, Qatar and the United Arab Emirates.

The United States of America is also not a member, although it originated from the 13 states on the country's eastern seaboard that were once British colonies, additional territory once claimed by the UK is now part of the country, and the two nations have long established cultural, military, and diplomatic ties. There are some suggestions that the original 13 states (as well as Maine and Vermont, which were at the time of British rule part of Massachusetts and New York, respectively) could possibly join the Commonwealth, but under Article 1, Section 10 of the US Constitution, individual states are forbidden from entering into any treaties, alliances, or confederations. If the US were to join the Commonwealth, all 50 states in the country, with most having never been ruled by the UK, would have to join as a whole under the US Federal Government. Such a situation is not without precedent, however, as is shown by the case of Cameroon, it is unlikely that the United States will ever seek membership in the Commonwealth.

Hong Kong could not join the Commonwealth following the end of British rule in 1997, as it became a special administrative region of the People's Republic of China.

France secretly considered membership in the 1950s, under the leadership of Prime Minister Guy Mollet. In the context of nationalisation of the Suez Canal, colonial unrest, and increasing tensions between British-backed Jordan and French-backed Israel, Mollet saw a union between Britain and France as a possible solution. A British Government document of the time reported "That the French would welcome a common citizenship arrangement on the Irish basis". The French economy was in a mess and the United Kingdom was seen as a social and economic role model in Paris. The request was turned down by the British prime minister Anthony Eden, along with a request for Commonwealth membership, and a year later France signed the Treaty of Rome with Germany and the other founding nations of the Common Market, later to become the EU. [6]

Current and possible future applicants
Rwanda and Yemen have applied to join the Commonwealth, and there was some interest expressed by the Palestinians.

It has also been suggested that Jordan, Israel, and Algeria, being formerly administered by the United Kingdom, might consider joining, while Zimbabwe and the Republic of Ireland could rejoin. A number of Irish politicians, notably cabinet minister Éamon Ó Cuív (a grandson of Éamon de Valera), have advocated rejoining, and the government of Seán Lemass considered doing so in the 1960s; Lemass in the mid 1960s had his Minister for Justice Brian Lenihan raise the issue. Lenihan described his actions as flying a kite to gauge the public reaction. In the aftermath of the 50th anniversary of the Easter Rising the idea was controversial and was dropped. It has been raised since by, among others, John M. Kelly (Minister for Foreign Affairs July-October 1981) and by Lenihan again in the late 1980s. The Taoiseach Bertie Ahern (1997-2007) has suggested that it is unlikely to happen. Others have suggested that it would be the final "piece in the jigsaw" for the current Northern Ireland peace process; bringing the Republic of Ireland and Northern Ireland closer.

Should Somaliland and Southern Sudan gain independence or international recognition it is likely they will want to join the Commonwealth too. Any internationally recognised split of the island of Cyprus might also see both the Greek and Turkish halves of the island as Commonwealth members (currently Cyprus is officially a unitary member of the Commonwealth).

Two nations with no historical links to the British Empire, Rwanda and Cambodia, have also applied to join, but their accession seems unlikely.

The various remaining territories and dependencies of the United Kingdom and several other Commonwealth countries would almost certainly gain admission to the Commonwealth in their own right should they become independent. These include Anguilla, Bermuda, the British Indian Ocean Territory (when residents are allowed to return), the British Virgin Islands, the Cayman Islands, Christmas Island, the Cocos Islands, the Cook Islands, the Falkland Islands (possibly including South Georgia which has no native population), Gibraltar, Guernsey, the Isle of Man, Jersey, Montserrat, Niue, Pitcairn, Saint Helena, the Turks and Caicos Islands, Tokelau and Norfolk Island.

The four nations that comprise the United Kingdom, England, Scotland, Wales, and Northern Ireland, have in recent years moved towards a system of asymmetrical devolution. The question of Scotland or Wales becoming independent nations is still very much part of the political scene in those nations as is Irish re-unification. There is also growing unrest in English political circles that England is badly represented in the current devolved settlement. Similarly, the island of Nevis, currently part of Saint Kitts and Nevis, may eventually separate from its larger neighbour. These would all be potential Commonwealth members in their own right.

Suspension
In recent years the Commonwealth has suspended several members "from the Councils of the Commonwealth" for failure to uphold democratic government. Suspended members are not represented at meetings of Commonwealth leaders and ministers, although they remain members of the organisation.

Fiji, which was not a member of the Commonwealth between 1987 and 1997 as a result of a republican coup d'état, was suspended in 2000–2001 after a military coup, as was Pakistan from 1999 until 2004. Fiji was suspended once again following the military coup of December 2006.

Nigeria was suspended between 1995 and 1999.

Zimbabwe was suspended in 2002 over concerns with the electoral and land reform policies of Robert Mugabe's Zanu-PF government, before withdrawing from the organization in 2003. It had previously been suspended from the Commonwealth under the country's former name of Rhodesia from its unilateral declaration of independence in 1965 until its internationally recognised independence as Zimbabwe in 1980.

Withdrawal
As membership is purely voluntary, member governments can choose at any time to leave the Commonwealth. Pakistan left in 1972 in protest at Commonwealth recognition of breakaway Bangladesh, but rejoined in 1989. Zimbabwe left in 2003 when Commonwealth Heads of Government refused to lift the country's suspension on the grounds of human rights violations and deliberate misgovernment.

Other termination
Although Heads of Government have the power to suspend member states from active participation, the Commonwealth has no provision for the expulsion of members. However, Commonwealth Realms that become republics automatically cease to be members, unless (like India in 1950) they obtain the permission of other members to remain in the organisation as a republic.

The Republic of Ireland left the Commonwealth when the Westminister act first came in, this allowed Commonwealth states to change laws without the consent of Westminster.

South Africa was prevented from continuing as a member after it became a republic in 1961, due to hostility from many members, particularly those in Africa and Asia as well as Canada, to its policy of apartheid. The South African government withdrew its application to remain in the organisation as a republic when it became clear at the 1961 Commonwealth Prime Ministers' Conference that any such application would be rejected. South Africa was re-admitted to the Commonwealth in 1994, following the end of apartheid in 1990.

The Maldives left the Commonwealth in 1965 after unilaterally declaring their independence from the United Kingdom; they were re-admitted to the Commonwealth on 9 July 1982.

The declaration of a republic in the Fiji Islands in 1987, after military coups designed to deny Indo-Fijians political power in Fiji, was not accompanied by application to remain. Commonwealth membership was held to have lapsed until 1997, after racist provisions in the republican constitution were repealed and reapplication for membership made.

Hong Kong was not a member but participated in certain elements as a British colony; these ceased after the 1997 handover of British rule to China.