The International Olympic Committee (IOC) allocates three-letter country codes to all National Olympic Committees and other groups competing in the Olympic Games. For historical reasons, many of these are different from the standard ISO 3166-1 codes.

Current codes

• AFG - Afghanistan
• AHO - Netherlands Antilles
• ALB - Albania
• ALG - Algeria
• AND - Andorra
• ANG - Angola
• ANT - Antigua and Barbuda
• ASA - American Samoa
• ARG - Argentina
• ARM - Armenia
• ARU - Aruba
• AUS - Australia
• AUT - Austria
• AZE - Azerbaijan
• BAH - The Bahamas
• BAN - Bangladesh
• BAR - Barbados
• BDI - Burundi
• BEL - Belgium
• BEN - Benin
• BER - Bermuda
• BHU - Bhutan
• BIH - Bosnia Herzegovina
• BIZ - Belize
• BLR - Belarus
• BOL - Bolivia
• BOT - Botswana
• BRA - Brazil
• BRN - Bahrain
• BRU - Brunei Darussalam
• BUL - Bulgaria
• BUR - Burkina Faso
• CAF - Central African Republic
• CAM - Cambodia
• CAN - Canada
• CAY - Cayman Islands
• CGO - Republic of the Congo
• CHA - Chad
• CHI - Chile
• CHN - People's Republic of China
• CIV - Côte d'Ivoire (also known commonly as the Ivory Coast)
• CMR - Cameroon
• COD - Democratic Republic of the Congo (formerly known as Zaire)
• COK - Cook Islands
• COL - Colombia
• COM - Comoros
• CPV - Cape Verde
• CRC - Costa Rica
• CRO - Croatia
• CUB - Cuba
• CYP - Cyprus
• CZE - Czech Republic
• DEN - Denmark
• DJI - Djibouti
• DMA - Dominica
• DOM - Dominican Republic
• ECU - Ecuador
• EGY - Egypt
• ERI - Eritrea
• ESA - El Salvador
• ESP - Spain
• EST - Estonia
• ETH - Ethiopia
• FIJ - Fiji
• FIN - Finland
• FRA - France
• FSM - Federated States of Micronesia
• GAB - Gabon
• GAM - The Gambia
• GBR - Great Britain and Northern Ireland (United Kingdom)
• GBS - Guinea-Bissau
• GEO - Georgia
• GEQ - Equatorial Guinea
• GER - Germany
• GHA - Ghana
• GRE - Greece
• GRN - Grenada
• GUA - Guatemala
• GUI - Guinea
• GUM - Guam
• GUY - Guyana
• HAI - Haiti
• HKG - Hong Kong, China (previously Hong Kong)
• HON - Honduras
• HUN - Hungary
• INA - Indonesia
• IND - India
• IRI - Islamic Republic of Iran
• IRL - Ireland
• IRQ - Iraq
• ISL - Iceland
• ISR - Israel
• ISV - U.S. Virgin Islands
• ITA - Italy
• IVB - British Virgin Islands
• JAM - Jamaica
• JOR - Jordan
• JPN - Japan
• KAZ - Kazakhstan
• KEN - Kenya
• KIR - Kiribati
• KGZ - Kyrgyzstan
• KOR - South Korea
• KSA - Saudi Arabia
• KUW - Kuwait
• LAO - Laos
• LAT - Latvia
• LBA - Libya
• LBR - Liberia
• LCA - Saint Lucia
• LES - Lesotho
• LIB - Lebanon
• LIE - Liechtenstein
• LTU - Lithuania
• LUX - Luxembourg
• MAD - Madagascar
• MAR - Morocco
• MAS - Malaysia
• MAW - Malawi
• MDA - Moldova
• MDV - Maldives
• MEX - Mexico
• MGL - Mongolia
• MKD - Former Yugoslav Republic of Macedonia
• MLI - Mali
• MLT - Malta
• MON - Monaco
• MOZ - Mozambique
• MRI - Mauritius
• MTN - Mauritania
• MYA - Myanmar (formerly Burma)
• NAM - Namibia
• NCA - Nicaragua
• NED - Netherlands
• NEP - Nepal
• NGR - Nigeria
• NIG - Niger
• NOR - Norway
• NRU - Nauru
• NZL - New Zealand
• OMA - Oman
• PAK - Pakistan
• PAN - Panama
• PAR - Paraguay
• PER - Peru
• PHI - Philippines
• PLE - Palestine
• PLW - Palau
• PNG - Papua New Guinea
• POL - Poland
• POR - Portugal
• PRK - North Korea
• PUR - Puerto Rico
• QAT - Qatar
• ROM - Romania
• RSA - South Africa
• RUS - Russia
• RWA - Rwanda
• SAM - Samoa
• SCG - Serbia and Montenegro (from the Serbian 'Crna Gora' for Montenegro)
• SEN - Senegal
• SEY - Seychelles
• SIN - Singapore
• SKN - Saint Kitts and Nevis
• SLE - Sierra Leone
• SLO - Slovenia
• SMR - San Marino
• SOL - Solomon Islands
• SOM - Somalia
• SRI - Sri Lanka
• STP - São Tomé and Príncipe
• SUD - Sudan
• SUI - Switzerland
• SUR - Suriname
• SVK - Slovakia
• SWE - Sweden
• SWZ - Swaziland
• SYR - Syria
• TAN - Tanzania
• TGA - Tonga
• THA - Thailand
• TJK - Tajikistan
• TKM - Turkmenistan
• TLS - Timor-Leste (also known commonly as East Timor)
• TOG - Togo
• TPE - Chinese Taipei (Republic of China, also known commonly as Taiwan)
• TRI - Trinidad and Tobago
• TUN - Tunisia
• TUR - Turkey
• UAE - United Arab Emirates
• UGA - Uganda
• UKR - Ukraine
• URU - Uruguay
• USA - United States
• UZB - Uzbekistan
• VAN - Vanuatu
• VEN - Venezuela
• VIE - Vietnam
• VIN - Saint Vincent and the Grenadines
• YEM - Yemen
• ZAM - Zambia
• ZIM - Zimbabwe

Historical codes

• ANZ - Australasia (1908–1912) combined Australia and New Zealand team
• BIR - Burma (1948–1992) - now MYA Myanmar.
• BOH - Bohemia (1900–1912) now CZE Czech Republic
• BOR - North Borneo (1956)
• BWI - British West Indies Federation (1960)
• DAH - Dahomey (1972) now BEN Benin.
• EUA - United Team of Germany (1956–1964) competed under a special flag.
• EUN - Unified Team (1992) former Soviet Union states marced under the Olympic Flag
• FRG - West Germany (1952 & 1968–1988)
• GDR - East Germany (1968–1988)
• IHO - Netherlands Indies (1952) now INA Indonesia
• IOA - Individual Olympic Athlete - used for East Timorese athletes competing under the Olympic Flag at the 2000 Games, during the United Nations Transitional Administration.
• IOP - Independent Olympic Participant - used for individual athletes from Yugoslavia competing under the Olympic Flag in the 1992 Summer Games when the country was under a United Nations sporting embargo.
• RAU - United Arab Republic (1960–1968) now EGY Egypt
• RHN - Northern Rhodesia (1964) now ZAM Zambia
• RHO - Rhodesia (1928–1960)
• RHS - Southern Rhodesia (1964) now ZIM Zimbabwe
• SAA - Saar (1952)
• TCH - Czechoslovakia (1920–1992)
• URS - Soviet Union (1956–1988)
• YAR - Yemen Arab Republic (1984–1988)
• YDR - People's Democratic Republic of Yemen (1988)
• YUG - Yugoslavia (1924–2000) now SCG Serbia and Montenegro.
• ZAI - Zaire (1968–1996) now COD Democratic Republic of the Congo.
• ZZX - Mixed Team: (1896–1904) retrospectively applied to teams of mixed nationality. These have not been possible since the advent of National Olympic Committees.