Countries expected to participate in the 2012 Summer Olympic Games in London include the following (in alphabetical order):
- Afghanistan
- Albania
- Andorra
- Antigua and Barbuda
- Angola
- Algeria
- Argentina
- Armenia
- Aruba
- Australia
- Austria
- Azerbaijan
- Bahamas
- Bangladesh
- Barbados
- Burundi
- Belgium
- Belize
- Benin
- Bermuda
- Bhutan
- Bolivia
- Bosnia-Herzegovina
- Bahrain
- Botswana
- Belarus
- Brazil
- British Virgin Islands
- Bulgaria
- Burkina Faso
- Cameroon
- Cambodia
- Canada
- Cayman Islands
- Central Africa
- Chad
- Chile
- China Republic
- Chinese Taipei
- Colombia
- Comoros
- Cape Verde
- Congo
- Cook Islands
- Costa Rica
- Cote-d´lvoire
- Croatia
- Cuba
- Cyprus
- Czech Republic
- Denmark
- Djibouti
- Dominica
- Dominican Republic
- Ecuador
- Arab Rep. of Egypt
- El Salvador
- Equatorial Guinea
- Eritrea
- Estonia
- Ethiopia
- Fiji
- Finland
- France
- Gabon
- The Gambia
- Germany
- Ghana
- Great Britain
- Guinea-Bissau
- Georgia
- Greece
- Grenada
- Guam
- Guatemala
- Guinea
- Guyana
- Haiti
- Honduras
- Hong Kong
- Hungary
- Iceland
- India
- Indonesia
- Iran
- Iraq
- Ireland
- Italy
- Israel
- Ivory Coast
- Jamaica
- Japan
- Jordon
- Kazakhstan
- Kyrgyzstan
- Kenya
- Korea people Republic
- Korea Democratic People Republic
- Kuwait
- Laos
- Latvia
- Saint Lucia
- Lebanon
- Lesotho
- Libya
- Lichtenstein
- Luxembourg
- Rep. of Macedonia
- Madagascar
- Malawi
- Malaysia
- Rep. of Moldova
- Marshall Islands
- Maldives
- Malta
- Mali
- Mauritania
- Mauritius
- Mexico
- Micronesia
- Monaco
- Montenegro
- Mongolia
- Morocco
- Mozambique
- Myanmar
- Namibia
- Nauru
- Nepal
- Netherlands
- Netherlands Antilles
- New Zealand
- Nicaragua
- Niger
- Nigeria
- Norway
- Oman
- Pakistan
- Palau
- Panama
- Papua New Guinea
- Palestine
- Paraguay
- Peru
- Philippines
- Poland
- Portugal
- Puerto Rico
- Qatar
- Rhodesia
- Romania
- Rwanda
- Saint Lucia
- St. Vincent & Gr.
- Saint Kitts and Nevis
- Samoa
- American Samoa
- Western Samoa
- San Marino
- Sao Tome and Principe
- Saudi Arabia
- Seychelles
- Sierra Leone
- Senegal
- Slovenia
- Solomon Islands
- South Africa
- Sri Lanka
- Slovakia
- Swaziland
- Serbia
- Singapore
- Spain
- Sudan
- Surinam
- Syria
- Sweden
- Switzerland
- Tanzania
- Tonga
- Thailand
- Togo
- Trinidad & Tobago
- Tajikistan
- Timor-Leste
- Turkmenistan
- Tunisia
- Turkey
- Tuvalu
- Uganda
- Ukraine
- Unified Team
- United Arab Emirates
- U.S.S.R.
- USA
- US Virgin Islands
- Uruguay
- Uzbekistan
- Vanuatu
- Venezuela
- Vietnam
- Yemen
- Yugoslavia
- Zambia
- Zimbabwe