The National Standard Examination in Junior Science or NSEJS is an examination in Science for secondary school students, usually conducted in the end of November. Organized by the Indian Association of Physics Teacher in association with Homi Bhabha Centre for Science Education (HBCSE), NSEJS is considered toughest Science exam on higher secondary level globally. The NSEJS is carried out every year since 1987 in English, Hindi & a few other Indian languages. More than 80,000 students from over 1,500 centres take part in these Olympiads

The top 300 students or so, with statewise quota, from this examination are selected to sit for the Indian National Junior Science Olympiad. The examination, with both a theory and an objective paper is held in the last week of January. The top 35 or so students are then called for an Orientation cum Selection Camp (OCSC), and the top 6 among all students are selected for the International Junior Science Olympiad.

Format Before 2014-15, The NSEJS comprised both multiple choice questions and subjective questions. Due to the large volume of participating students, all questions were not checked for all candidates; subjective questions were checked for only those candidates scoring above a certain minimum in the multiple choice questions. Multiple choice questions carried about 60% of the total weightage and were the crucial determinant for selection to the next stage. The present format (from 2014-15 onwards) is composed entirely of 80 multiple-choice questions.

To be eligible to get to the next level, i.e. the second stage, it is necessary that a student scores at-least a Minimum Admissible Score (MAS) which is 50% of the maximum score