The International Junior Science Olympiad (IJSO) is the science olympiad for younger students. Where the senior olympiads each focus on one subject, IJSO tests physics, chemistry and biology together, at roughly the level of a strong Class 10 student, including experiments.
India selects its IJSO team through a five-stage programme that starts with a single paper, NSEJS. This guide explains each stage as it currently runs, who is eligible, what the papers look like and how to prepare. It is written for parents and for students in Classes 8 to 10 thinking of giving it a go. Details change every year, so always confirm them on the IAPT site and the IAPT junior science olympiad site before registering.
Who runs it
The whole junior science pathway is run by the Indian Association of Physics Teachers (IAPT), a voluntary organisation of physics teachers. IAPT has long set the first stage. Since 2022–23 it has also run the later stages, which were earlier handled by the Homi Bhabha Centre for Science Education (HBCSE). HBCSE continues to run the later stages of the senior olympiads in physics, chemistry, biology and astronomy.
The five stages
| Stage | Name | What happens | Usually held |
|---|---|---|---|
| 1 | NSEJS | Objective paper written at centres across India | Late November |
| 2 | INJSO | Harder national paper for the top NSEJS performers | Late January or early February |
| 3 | OCSC | Orientation-cum-selection camp with theory and experiments | Between April and June |
| 4 | Pre-departure training | Further training for the selected team | Before IJSO |
| 5 | IJSO | The international olympiad | Towards the end of the year |
So a student who writes NSEJS in November of one year would, if selected, travel to IJSO roughly a year later.
Stage 1: NSEJS
The National Standard Examination in Junior Science is one of IAPT’s five National Standard Examinations, alongside those in physics, chemistry, biology and astronomy.
The syllabus is broadly equivalent to Class 10 of the CBSE in science, with physics, chemistry and biology given equal emphasis; maths up to the same level is expected too. The questions are harder than board exam questions, because they test whether you can apply ideas to situations you haven’t seen before.
The paper, in its recent format, is two hours long and has two parts: 48 multiple-choice questions with one correct answer each, where a wrong answer loses a mark, and 12 harder questions where one or more options may be correct and you get credit only if you mark all the correct options and none of the wrong ones. It is offered in English and Hindi.
Who can write it. Eligibility is set by date of birth, not class. For the 2026 exam, students born in 2012 or 2013 were eligible, provided they met the other conditions: being eligible for an Indian passport, having lived and studied in India (or in the Indian school system) for a set period, and not having finished Class 10 board exams before the exam. Because the window is set by birth year, it usually covers most students in Class 9, many in Class 8 and some in Class 10. Check your child’s date of birth against the current brochure rather than going by class.
A student can’t write NSEJS and one of the senior National Standard Examinations in the same year.
How to register. Most students enrol through their own school, which registers as an exam centre. Students whose school doesn’t take part can enrol online through IAPT. Enrolment usually opens in August.
Recognition. Even students who don’t go further can earn something. IAPT’s brochure describes certificates for the top 10% at each centre, merit certificates for the top 1% in each state, and special merit certificates for the national top 1% in junior science.
Stage 2: INJSO
The Indian National Junior Science Olympiad is a harder written paper on the same Class 10-level syllabus. A few hundred students are selected for it from NSEJS, through rules that combine national merit with representation from every state. That means the cut-off can differ from state to state.
Students selected for INJSO must complete any registration IAPT asks for in time; missing it can mean losing the place.
Stage 3: the selection camp
The top INJSO performers are invited to an Orientation-cum-Selection Camp. Here the focus widens to include laboratory work, as IJSO itself includes experimental tasks. Students are taught and tested over the camp, and the Indian team is chosen on that basis. IAPT’s brochure says every student who attends a selection camp receives a gold medal.
Stages 4 and 5: training and IJSO
The selected team goes through pre-departure training before travelling to IJSO, which brings together teams from many countries for theory and experimental papers. IJSO has an upper age limit, which is why NSEJS uses a birth-date window.
How to prepare
Start with school science, properly
NSEJS rewards a deep grasp of Class 8 to 10 science far more than knowledge of advanced topics. Make sure the NCERT science books for these classes are genuinely understood, not memorised: why a reaction happens, what a graph shows, how an experiment controls for other factors. Work through the in-text questions and exercises, then look for harder applications of the same ideas.
Don’t neglect maths
Many physics and chemistry questions involve calculation, ratios, graphs and units. Comfortable, accurate maths up to Class 10 saves time and marks.
Use past papers early
IAPT publishes past NSEJS papers. Try one early, untimed, to see the style, then use them throughout. For each mistake, note whether it was a gap in knowledge, a misread question or a calculation slip.
Learn the marking
With a penalty for wrong answers in the first part, and all-or-nothing marking in the second, careless guessing costs marks. Practise deciding when you are confident enough to answer. In the second part, mark only the options you can justify.
Practise the clock
Sixty questions in two hours leaves about two minutes per question, and some take much longer than others. From a few weeks before the exam, write full papers under time, and practise moving on from a question that is taking too long.
Think like an experimenter
Even before the camp stage, practical thinking helps: reading data from tables and graphs, spotting sources of error, and predicting what a change in one variable will do. School lab work, done carefully, is good preparation.
A rough timeline for a Class 9 student
- Summer: finish a careful pass through Class 9 science and the parts of Class 10 science already started; try one past paper untimed.
- August to September: enrol through school; work on weak topics; one past paper every two weeks.
- October to November: a timed paper each week, with thorough review; keep sessions regular rather than long.
Keep school work and sleep in the plan. Steady practice over months does more than a final rush.
After NSEJS
The junior pathway leads naturally to the senior one. From Class 10 to Class 12, students within the birth-date window can write the National Standard Examinations in physics, chemistry, biology and astronomy, leading to the Indian National Olympiads run by HBCSE and the international olympiads in each subject. A strong NSEJS year is a good foundation for any of them. For the maths route, read the road to the IMO, and for how far olympiad results go in admissions, read are olympiads worth it for college?
Ado is not affiliated with IAPT or HBCSE.
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