Overview
SOF's science talent exam, long known as the National Science Olympiad (NSO), has been rebranded the International Science Olympiad (ISO) by the Science Olympiad Foundation (SOF) from the 2026-27 cycle, though "NSO" is still widely used. It is a privately organised, school-based competition testing scientific reasoning for students from Class 1 to Class 12, run separately from any government science talent search or olympiad.
Who can take part
Students enrolled in a SOF-recognised school, from Class 1 to Class 12, can take Level 1. Level 2 is open only to students in Class 3 and above who rank among the top 5% of participants (by class) in Level 1; there is no separate Level 2 for Classes 1–2.
Stages and pathway
| Level | Who appears | What decides advancement |
|---|---|---|
| Level 1 | All registered students, Classes 1–12 | Top 5% of each class advance to Level 2 (Classes 3–12 only) |
| Level 2 | Top 5% of Level 1 (Classes 3–12) | International, zonal and school-level ranks and awards |
Exam pattern
| Detail | SOF NSO/ISO |
|---|---|
| Format | Multiple-choice questions and problem-solving tasks |
| Duration | 1 hour |
| Mode | Offline (in school) |
| Language | English |
Syllabus
The exam covers school science topics appropriate to each class, including areas such as metals and non-metals, carbon compounds, reproduction, electricity, magnetic effects, and control and coordination for the senior classes.
Results and awards
Level 2 qualifiers receive international, zonal and school-level recognition. The top three international rank holders in each class receive cash awards, medals and certificates.
Important dates
For the 2026-27 cycle, Level 1 is offered on three alternative dates — Friday, October 30, 2026; Thursday, November 19, 2026; and Thursday, December 3, 2026 — and each school picks one date for its students. Level 2 is tentatively scheduled for the second or third Sunday of February 2027.
Fees
The registration fee is Rs. 170 per student per Olympiad (inclusive of GST) for schools in India, Bhutan and Nepal, or US$11 for schools outside these countries. Schools may additionally charge up to Rs. 30 per student to cover administrative costs.
How to register
Registration is done only through schools, at least 30 days before the school's chosen exam date — SOF does not accept applications directly from individual students. A school must itself be registered with SOF; new schools can register by contacting SOF's office.
Preparation tips
Since each class has a separate paper matched to that class's syllabus, working through the regular school science syllabus first and then SOF's own sample papers and previous years' question papers gives the most direct preparation.
Is NSO the same exam as ISO?
Yes. SOF has renamed its science olympiad from National Science Olympiad (NSO) to International Science Olympiad (ISO) from the 2026-27 cycle; both names refer to the same exam.
Can a student register individually, without a school?
No. SOF accepts registrations only through schools that are themselves registered with SOF.
Does every student who takes Level 1 move on to Level 2?
No. Only the top 5% of participants in each class advance to Level 2, and Level 2 itself is open only from Class 3 upward.
How much does SOF NSO/ISO cost?
The fee is Rs. 170 per student (inclusive of GST) for schools in India, Bhutan and Nepal, plus up to Rs. 30 the school may add for administration.