Overview
The International Junior Science Olympiad (IJSO) is an annual individual and team competition in the natural sciences for younger students. It combines physics, chemistry and biology in one contest. The website describes it as a purely educational event that aims to reward excellence in science and to build friendships between young people from different countries. The details below follow the 2019 statutes posted on the website.
Who can take part
Students must be under sixteen on 31 December of the competition year; the 2019 statutes word this as fifteen years old or younger.
A normal national team has six students and three team leaders. If a country cannot send a full team, a minimum team of three students and at least one leader is allowed. Teams with fewer than three students are not classified for team awards.
The host country may have two national delegations.
Students are selected through each country's own national process.
Exam pattern
The competition has three examination papers, held on three days with at least one day between them. Each should normally take three to four hours.
| Paper | Format |
|---|---|
| Multiple-choice | 30 questions, 10 each in physics, biology and chemistry, with four options and one correct answer. Individual |
| Theoretical | Questions that combine physics, chemistry and biology, more complex than the multiple-choice paper. Individual |
| Practical (experimental) | The three sciences in equal proportion. A team test, with one team of three students per delegation, and each country may enter two teams |
Medals
For individual results, about the top 10 percent receive gold, the next 20 percent silver and the next 30 percent bronze, and medals must not exceed 60 percent of students. In the team practical, the highest-scoring team receives gold medals, the second silver and the third bronze, one to each team member.
Next edition
The IJSO website states that IJSO 2026 is to be held in Sofia, Bulgaria, with registration open from 1 to 31 August 2026.
How to take part
Entry is only through your country's national junior science olympiad or selection programme. Ask your national olympiad office about the stages and the age cut-off.
Preparation tips
Revise school physics, chemistry and biology to the level of the IJSO syllabus on the official site.
Practise experiments, since one paper is practical and done in a team.
Solve past IJSO papers published by earlier hosts.
Note
The age limit, team size and test formats are set in the statutes and can be amended. Confirm them on the official website before registering.