The flag of the international Olympic movement
The flag of the international Paralympic movement
The International Olympic Committee (IOC) uses three-letter abbreviation country codes to refer to each group of athletes that participate in the Olympic Games. Each code usually identifies a National Olympic Committee, but there are several codes that have been used for other instances in past Games, such as teams composed of athletes from multiple nations, or groups of athletes not formally representing any nation.
Several of the IOC codes are different from the standard ISO 3166-1 alpha-3 codes. Other sporting organisations, such as FIFA or the Commonwealth Games Federation, use similar country codes to refer to their respective teams.
The 1956 Winter Olympics and 1960 Summer Olympics were the first Games to feature Initials of Nations to refer to each NOC in the published official reports. However, the codes used at the next few Games were often based on the host nation's language (e.g., GIA for Japan at the 1956 Winter Olympics and 1960 Summer Olympics, both held in Italy, from Italian Giappone) or based on the French name for the nation (e.g., COR for Korea, from Corée). By the 1972 Winter Olympics, most codes were standardized on the current usage, but several have changed in recent years. Additionally, the dissolution of the Soviet Union, division and unification of Germany, breakup of Yugoslavia, dissolution of Czechoslovakia, and several other instances of geographical renaming have all resulted in code changes.
In addition to this list of over 200 NOCs, the participation of National Paralympic Committees (NPCs) at the Paralympic Games requires standardised IOC codes. namely Macau and the Faroe Islands, coded MAC and FRO respectively.
Current NOCs 
There are 204 current NOCs (National Olympic Committees) within the Olympic Movement. The following tables show the currently used code for each NOC and any different codes used in past Games, per the official reports from those Games. Some of the past code usage is further explained in the following sections. Codes used specifically for a Summer Games only or a Winter Games only, within the same year, are indicated by "S" and "W" respectively.
||Other codes used
||Other codes used
||Other codes used
Historic NOCs and teams 
Codes still in use 
Fourteen historical NOCs or teams have codes that are still used in the IOC results database to refer to past medal winners from these teams.
||Other codes used
|| Netherlands Antilles
|| British West Indies
||ANT (1960, 1968), WID (1964)
|| Unified Team of Germany
|| Unified Team
|| West Germany
||ALL (1968 W), ALE (1968 S), GER (1972–1976)
|| East Germany
|| Russian Empire
|| Serbia and Montenegro
||YUG (1996 S-2002 W)
||CSL (1956 W), CZE (1960 W), CSV (1960 S), CZS (1964 S), CHE (1968 S)
|| Soviet Union
||SOV (1968 W)
||JUG (1956–1960, 1968 W), YUS (1964 S)
|| Mixed teams
Obsolete codes 
Two other significant code changes have occurred, both because of a change in the nation's designation as used by the IOC:
- HOL was changed to NED for the Netherlands for the 1992 Games, reflecting the change in designation from Holland.
- IRN was changed to IRI for Iran for the 1992 Games, reflecting the change in designation to Islamic Republic of Iran.
Special codes 
- ANZ is now used in the IOC's medal database to identify the team from Australasia, composed of athletes from both Australia and New Zealand for the 1908 and 1912 Games. By 1920, both nations competed separately.
- EUA is now used in the IOC's medal database to identify the Unified Team of Germany, composed of athletes representing the NOCs of both East Germany and West Germany for the 1956–1964 Games. At the time, the team was simply known as Germany in the official reports for those six Games.
- EUN was used in 1992 (both Summer and Winter Games) for the Unified Team, composed of athletes from most of the ex-republics of the Soviet Union. Only the Baltic states were able to compete as independent teams in 1992; the other twelve new nations competed independently for the first time in 1994 and/or 1996.
- IOP was used for Independent Olympic Participants in 1992, a designation used for athletes from Yugoslavia who could not compete as a team due to United Nations sanctions.
- IOA was used for Individual Olympic Athletes in 2000, a designation used for athletes from Timor-Leste prior to the formation of its NOC. IOA will was used again in the 2012 Games. In 2012 it stood for Independent Olympic Athletes, which comprised athletes from the former Netherlands Antilles and a runner from South Sudan. The Netherlands Antilles Olympic Committee's membership from the IOC was withdrawn the previous year, and South Sudan has not formed an NOC.
- IOC was used as the country code for Athletes from Kuwait at the 2010 Asian Games, as the Kuwait Olympic Committee was suspended.
- ZZX is used to identify medals won by mixed teams of athletes from multiple nations (such as the combination of France and Great Britain, for example), a situation that happened several times in the Games of 1896, 1900, and 1904.
See also 
- VII Olympic Winter Games Cortina d'Ampezzo 1956 Official Report (PDF). Rome: Società Grafica Romana. p. 70. Retrieved 2008-01-31.
- (ed.) Robert Rubin. VIII Olympic Winter Games Squaw Valley California 1960 Final Report (PDF). California Olympic Commission. p. 92. Retrieved 2008-01-31.
- (ed.) Giacomini, Romolo (May 1963). The Games of the XVII Olympiad Rome 1960, The Official Report of the Organizing Committee, Volume 2 (PDF). Rome: Carlo Colombo. p. 56. Retrieved 2008-02-04.
- The Official Report of the Games of the XVIII Olympiad, Tokyo 1964, Volume II (PDF). Tokyo: The Organizing Committee for the Games of the XVIII Olympiad. October 1966. p. 1. Retrieved 2008-02-04.
- Xth Winter Olympic Games Official Report (PDF). Comité d'Organisation des xèmes Jeux Olympiques d'Hiver de Grenoble. 1969. p. 401. Retrieved 2008-01-31.
- (ed.) Trueblood, Beatrice (1969). The Official Report of the Organizing Committee of the Games of the XIX Olympiad Mexico 1968, Volume 3: The Games (PDF). Organizing Committee of the Games of the XIX Olympiad. pp. 16–17. Retrieved 2008-02-05.
- The Official Report of XIth Winter Olympic Games, Sapporo 1972 (PDF). The Organizing Committee for the Sapporo Olympic Winter Games. 1973. pp. 434–455. ISBN 0-900315-05-9. Retrieved 2008-01-31.
- (ed.) Kunze, Herbert (1974). The official report of the Organizing Committee for the Games of the XXth Olympiad Munich 1972, Volume 3 The competitions (PDF). Munich: proSport. p. 14. Retrieved 2008-02-04.
- (ed.) Bertl Neumann. XII.Olympische Winterspiele Innsbruck 1976 Final Report (PDF). Organizing Committee for the XIIth Winter Olympic Games 1976 at Innsbruck. p. 163. Retrieved 2008-01-31.
- (ed.) Chantigny, Louis (1978). Games of the XXI Olympiad Montréal 1976 Official Report, Volume III Results (PDF). Montreal: COJO 76. p. 7. Retrieved 2008-02-05.
- (ed.) I. T. Novikov (1981). Games of the XXII Olympiad Moscow 1980, Volume 3 Participants and Results (PDF). Moscow: Fizkultura i Sport. pp. 9–10. Retrieved 2008-02-05.
- Official Report of the Organising Committee of the XlVth Winter Olympic Games 1984 at Sarajevo (PDF). Sarajevo: Oslobodenje. 1984. pp. 89–90. Retrieved 2008-01-31.
- (ed.) Perelman, Richard B. (1985). Official Report of the Games of the XXIIIrd Olympiad Los Angeles 1984, Volume 2 Competition Summary and Results (PDF). Los Angeles Olympic Organizing Committee. p. 202. ISBN 0-9614512-0-3. Retrieved 2008-02-05.
- (ed.) Rodney Chapman (1988). XV Olympic Winter Games Official Report (PDF). Calgary Olympic Development Association. pp. 621–645. ISBN 0-921060-26-2. Retrieved 2008-01-31.
- (ed.) Lee Kyong-hee (September 1989). Games of the XXIVth Olympiad Seoul 1988 Official Report, Volume 2: Competition Summary and Results (PDF). Seoul Olympic Organizing Committee. pp. 150–161. Retrieved 2008-02-05.
- (ed.) Claudie Blanc, Jean-Marc Eysseric (1992). "Results" (PDF). Official Report of the XVI Winter Olympic Games of Albertville and Savoie. Albertville, France: Comité d'organisation des XVIes Jeux olympiques d'hiver d'Albertville et de la Savoie. p. 3. ISBN 2-9507109-0-5. Retrieved 2008-01-31.
- (ed.) Cuyàs, Romà (1992). Official Report of the Games of the XXV Olympiad Barcelona 1992, Volume IV The Games (PDF). COOB'92. pp. 396–397. ISBN 84-7868-097-7. Retrieved 2008-02-05.
- "Volume IV" (PDF). Official Report of the XVII Olympic Winter Games. 1994. p. 63. Retrieved 2008-01-31.
- (ed.) Watkins, Ginger T. (1997). The Official Report of the Centennial Olympic Games, Volume III The Competition Results (PDF). Atlanta: Peachtree Publishers. pp. viii–ix. ISBN 1-56145-150-9. Retrieved 2008-02-05.
- (ed.) Shinano Mainichi Shimbun (1998). "Volume Three Competition Results and Participants" (PDF). The XVIII Olympic Winter Games Official Report. The Organizing Committee for the XVIII Olympic Winter Games, Nagano 1998. p. 12. ISBN 4-7840-9827-5. Retrieved 2008-01-31.
- Sydney Organising Committee for the Olympic Games. (2001). "National Olympic Committees" (PDF). Official Report of the XXVII Olympiad, Volume Three: Results. Sydney Organising Committee for the Olympic Games. pp. 1–5. ISBN 0-9579616-1-8. Retrieved 2008-02-05.
- "List of National Olympic Committees Participating in the XIX Olympic Winter Games in Salt Lake City" (PDF). International Olympic Committee. 2002-01-30. Retrieved 2008-02-07.
- (ed.) Skarveli, Efharis; Zervos, Isabel (November 2005). Official Report of the XXVIII Olympiad, Volume Two: The Games (PDF). Athens 2004 Organising Committee for the Olympic Games. pp. 528–529. ISBN 960-88101-7-5. Retrieved 2008-02-05.