The International Olympic Committee (IOC) uses three letter acronym 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 organizations, such as FIFA or the Commonwealth Games Federation, use similar country codes to refer to their respective teams.