International Astronomy Olympiad (IAO)

The International Astronomy Olympiad (IAO) is an annual international competition in astronomy for middle and high school students, organised under the Olympic Coordinating Council (OCC) and the Euro-Asian Astronomical Society (EAAS). The event aims to disseminate astronomical knowledge, encourage scientific research and international exchanges in astronomy and physics, and to identify and support talented young students.

The Olympiad is typically hosted each autumn at a participating country for a period of about 8 to 10 days. The competition format includes a Theoretical Round (approximately 4 hours, 5-6 questions, total 40-48 points), a Practical Round (3-4 hours, 1-2 questions, total ~20 points based on research data provided by the host), and an Observational Round (nighttime outdoor observations, 1-3 questions, total ~20 points; may be moved indoors if weather prevents observation).

Eligibility is divided into juniors and seniors with specific age and participation restrictions: juniors must be age 15 or under as of January 1 of the Olympiad year and must not have prior Olympiad participation; seniors are typically students in their graduating year with age caps that depend on prior participation. Each country may send up to three juniors and two seniors; former gold/silver winners may attend as supernumerary members if they meet age rules.