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 to the standard ISO 3166-1 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
 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

Codes no longer used:

 BOH Bohemia
 EUN Unified Team (former Soviet Union, 1992)
 FRG West Germany
 GDR East Germany
 TCH Czechoslovakia
 URS Soviet Union
 YUG Yugoslavia