The International Olympiad in Informatics (IOI) is an annual international programming competition for secondary school students. Each country selects four student to participate. They compete on two competition days, each five hours long. Each day, they are given three tasks that they must solve by writing programs. Computers are supplied with the appropriate software. The programming languages and operating systems can change, but are currently C, C++ and Pascal. Multiple countries are pushing for including Java in future years.

To compete in the IOI, you must be a secondary school student and your country must select you. Most countries have competitions, such as the USA Computer Olympiad (USACO) and the British Informatics Olympiad. Small countries often have very ad-hoc methods to select their team.

For contestants, IOI is a combination of competition, sight-seeing, and socialization. The IOI is generally eight days long, only two of which are competition days. The remaining six days are spent seeing the country in which the IOI is held and talking to contestants from other countries.

The competition itself is an individual contest. Your score on the six tasks are summed to get your total. Based on your score, you may receive a bronze, silver, or gold medal. Unlike an Olympic event, multiple medals of each type are given. For every 12 contestants, approximately one gold, two silver and three bronze medals are awarded. Thus, about half the contestants get some medal. The top three scores receive extra recognition (usually including a free computer). Although not officially rank, the coaches and contestants rank countries on both total points and medal counts.

The tasks in the competition are being done by high school students, but are generally freshman-level to junior-level programming tasks, since the competition consists of the best four students from each country.

Organizational Notes: Like the other International Olympiads, the IOI was formed under UNESCO. The IOI's International Committee selects the country in which each IOI will be held. That country then locates funding, organizes, and operates the IOI under the rules of the IOI and with the approval of the General Assembly. The General Assembly consists of one coach from each country attending. The first IOI was held in 1989 in Bulgaria.